Patent Publication Number: US-11379457-B2

Title: Management of log data

Description:
INCORPORATION BY REFERENCE TO ANY PRIORITY APPLICATIONS 
     This disclosure is a continuation of U.S. patent application Ser. No. 15/475,746 filed on Mar. 31, 2017, the disclosure of which is hereby incorporated by reference in its entirety and which claims the benefit of priority of U.S. patent application Ser. No. 14/683,005 filed on Apr. 9, 2015 (issued as U.S. Pat. No. 9,934,265), the entirety of which is incorporated herein by reference. Any and all applications, if any, for which a foreign or domestic priority claim is identified in the Application Data Sheet of the present application are hereby incorporated by reference under 37 CFR 1.57. 
    
    
     BACKGROUND 
     Businesses worldwide recognize the commercial value of their data and seek reliable, cost-effective ways to protect the information stored on their computer networks while minimizing impact on productivity. Protecting information is often part of a routine process that is performed within an organization. A company might back up critical computing systems such as databases, file servers, web servers, and so on as part of a daily, weekly, or monthly maintenance schedule. The company may similarly protect computing systems used by each of its employees, such as those used by an accounting department, marketing department, engineering department, and so forth. 
     Given the rapidly expanding volume of data under management, companies also continue to seek innovative techniques for managing data growth, in addition to protecting data. For instance, companies often implement migration techniques for moving data to lower cost storage over time and data reduction techniques for reducing redundant data, pruning lower priority data, etc. Enterprises also increasingly view their stored data as a valuable asset. Along these lines, customers are looking for solutions that not only protect and manage, but also leverage their data. For instance, solutions providing data analysis capabilities, information management, improved data presentation and access features, and the like, are in increasing demand. 
     SUMMARY 
     One issue that arises with management of a computing environment involves the log data that systems and/or applications in the computing environment may automatically generate in association with the execution of transactions that are conducted in the computing environment. Such log data may comprise one or more log data files that capture transaction information for a system or an application. Users overseeing the computing environment may review the logs to obtain information regarding the transactions (e.g., as to whether particular transactions were successfully completed or resulted in errors). In the case of a catastrophic failure, certain transactions recorded in the log data may be replayed to restore the system or application to a pre-failure state. 
     However, these log data are typically very large. For example, the system or application generating such log data may be performing tens, hundreds, or thousands of transactions per second and may record multiple log entries for each of those transactions in a log data file, thereby generating millions or even billions of log entries that need to be processed and organized for presentation to a user of the system or application. Processing such a large number of log entries manually is not practical because sheer number of such log entries prevents users from being able to manually review them in a meaningful way. Accordingly, computer systems disclosed herein may be used to process and organize the log entries and distill them down to a format understandable by users. In some embodiments, such computer systems may chronologically or alphabetically sort the log file information for presentation to the user. However, in such embodiments, even if the log entries are sorted in such a manner, unless the user reviewing the log entries knows what to expect in the log data file (e.g., what kind of errors or warnings might appear in the log data file), the user may have trouble digesting the information in the log data file in a useful manner. For example, in order to determine what kind of errors the system has encountered, the user may simply be required to comb through all the log entries, which may be impractical. The user may overlook some of the log entries, further decreasing the utility of such log data files. For example, if the log data file of a certain application contains 1,000,000 out-of-memory errors, 500,000 database warnings, and 10 critical hacking attempts, unless the user knows exactly where to look for such hacking attempts, the chances of the user spotting them are rather slim. 
     Thus, an improved method of organizing log data in a way that facilitates the use of the information contained in the log data is desired. 
     A system according to certain aspects of the present disclosure can improve the process of processing and organizing log data generated by an application, such as log data generated during data storage and other operations conducted by a data storage system. The system can process the log data generated by the application store and organize the log entries contained in the log data into one or more groups for presentation to a user. In one example, the process of categorizing the log entries is performed by calculating a fingerprint value for each log entry and assigning the log entries into the one or more groups based on the calculated fingerprint values. 
     One aspect of the disclosure provides a method for processing log data. The method may include receiving a log data file comprising one or more log lines, where the log lines may include information relating to one or more computing operations. At least some of the log lines may include a static portion and a variable portion. The method may further include processing a first log line to identify the static portion of the first log line, extracting the static portion from the first log line, and determining a first value for the first log line based on the extracted static portion. The method may further include processing a second log line to identify the static portion of the second log line, extracting the static portion from the second log line, and determining a second value for the second log line based on the extracted static portion. The method may further include comparing the first and second values, and based on the comparison, organizing the first and second log lines together for presentation to a user. 
     The method of the preceding paragraph can have any sub-combination of the following features: where the first and second values are the same and uniquely identify the static portion of text of the first log line and the second log line; where said organizing comprises adding the first and second log lines to a group of log lines based on the first and second values, wherein the log lines in the group of log lines are associated with a unique set of values that are not associated with any other group; where the method further includes extracting a variable portion from the first log line, determining a third value for the first log line based on the extracted variable portion, extracting a variable portion from the second log line, and determining a fourth value for the second log line based on the extracted variable portion; where said organizing comprises adding the first and second log lines to a group of log lines based on the first and second values, wherein the log lines in the group of log lines are associated with values that are identical to the first and second values, and adding the first and second log lines to a sub-group within the group of log lines based on the third and fourth values, wherein the log lines in the sub-group are associated with values that are identical to the third and fourth values; where said determining of the first and second values comprises determining the first and second values using a hash function configured to generate a value based on the extracted static portions of the first and second log lines, respectively; where said determining of the first and second values comprises extracting a first set of one or more trigrams from the extracted static portion of the first log line and a second set of one or more trigrams from the extracted static portion of the second log line, calculating a value for each of the first and second sets of one or more trigrams, and determining the first and second values by aggregating the values calculated for the first and second sets of one or more trigrams, respectively; where the values calculated for the first and second sets of one or more trigrams are aggregated by calculating a sum of the values; where the static portions of the first and second log lines indicate the types of transaction associated with the first and second log lines, respectively, and variable portions of the first and second log lines indicate additional information regarding the transactions associated with the first and second log lines, respectively; and where said extracting of the static portion comprises determining a sequence of characters that have been processed more than a threshold number of times in the history of processing the log data. 
     Another aspect of the disclosure provides a system for processing log data. The system may include a computing device comprising computer hardware and configured to receive a log data file including one or more log lines. The log lines may include information relating to one or more computing operations. At least some of the log lines may include a static portion and a variable portion. The computing device may be further configured to process a first log line to identify the static portion of the first log line, extract the static portion from the first log line, and determine a first value for the first log line based on the extracted static portion. The computing device may be further configured to process a second log line to identify the static portion of the second log line, extract the static portion from the second log line, and determine a second value for the second log line based on the extracted static portion. The computing device may be further configured to compare the first and second values, and based on the comparison, organize the first and second log lines together for presentation to a user. 
     The system of the preceding paragraph can have any sub-combination of the following features: where the first and second values are the same and uniquely identify the static portion of text of the first log line and the second log line; where the computing device is configured to organize the first and second log lines at least by adding the first and second log lines to a group of log lines based on the first and second values, wherein the log lines in the group of log lines are associated with a unique set of values that are not associated with any other group; where the computing device is further configured to extract a variable portion from the first log line, determine a third value for the first log line based on the extracted variable portion, extract a variable portion from the second log line, and determine a fourth value for the second log line based on the extracted variable portion; where the computing device is configured to organize the first and second log lines at least by adding the first and second log lines to a group of log lines based on the first and second values, wherein the log lines in the group of log lines are associated with values that are identical to the first and second values, and adding the first and second log lines to a sub-group within the group of log lines based on the third and fourth values, wherein the log lines in the sub-group are associated with values that are identical to the third and fourth values; where the computing device is configured to determine the first and second values at least by determining the first and second values using a hash function configured to generate a value based on the extracted static portions of the first and second log lines, respectively; where the computing device is configured to determine the first and second values at least by extracting a first set of one or more trigrams from the extracted static portion of the first log line and a second set of one or more trigrams from the extracted static portion of the second log line, calculating a value for each of the first and second sets of one or more trigrams, and determining the first and second values by aggregating the values calculated for the first and second sets of one or more trigrams, respectively; where the values calculated for the first and second sets of one or more trigrams are aggregated by calculating a sum of the values; where the static portions of the first and second log lines indicate the types of transaction associated with the first and second log lines, respectively, and variable portions of the first and second log lines indicate additional information regarding the transactions associated with the first and second log lines, respectively; and the computing device is configured to extract the static portion at least by determining a sequence of characters that have been processed more than a threshold number of times in the history of processing the log data. 
     Another aspect of the disclosure provides a non-transitory computer readable medium comprising code that, when executed, causes an apparatus to perform a process that includes receiving a log data file containing one or more log lines. The log lines may include information relating to one or more computing operations, and at least some of the log lines may include a static portion and a variable portion. The process may further include processing a first log line to identify a static portion of the first log line, extracting the static portion from the first log line, and determining a first value for the first log line based on the extracted static portion. The process may further include processing a second log line to identify a static portion of the second log line, extracting the static portion from the second log line, and determining a second value for the second log line based on the extracted static portion. The process may further include comparing the first and second values, and based on the comparison, organizing the first and second log lines together for presentation to a user. 
     For purposes of summarizing the disclosure, certain aspects, advantages, and novel features of the inventions have been described herein. It is to be understood that not necessarily all such advantages may be achieved in accordance with any particular embodiment of the invention. Thus, the invention may be embodied or carried out in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other advantages as may be taught or suggested herein. 
     According to certain embodiments, a method is provided for processing log data. The method can include, with one or more computing devices comprising computer hardware, receiving a log data file comprising one or more log lines. The method can further include extracting a static portion from a first log line of the one or more log lines, determining a first value for the first log line based on the extracted static portion, and processing the first log line based on the first value determined for the first log line. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  is a block diagram illustrating an exemplary information management system. 
         FIG. 1B  is a detailed view of a primary storage device, a secondary storage device, and some examples of primary data and secondary copy data. 
         FIG. 1C  is a block diagram of an exemplary information management system including a storage manager, one or more data agents, and one or more media agents. 
         FIG. 1D  is a block diagram illustrating a scalable information management system. 
         FIG. 1E  illustrates certain secondary copy operations according to an exemplary storage policy. 
         FIGS. 1F-1H  are block diagrams illustrating suitable data structures that may be employed by the information management system. 
         FIG. 2A  is a block diagram illustrating an exemplary system configured to implement improved log data management, according to an illustrative embodiment. 
         FIG. 2B  is a block diagram illustrating another exemplary system configured to implement improved log data management, according to an illustrative embodiment. 
         FIG. 3  is flow diagram illustrative of one embodiment of processing log data. 
         FIG. 4  is flow diagram illustrative of one embodiment of calculating a fingerprint. 
         FIG. 5  is flow diagram illustrative of one embodiment of monitoring log data. 
         FIGS. 6 and 7  are illustrative examples of displaying log data. 
     
    
    
     DETAILED DESCRIPTION 
     Systems and methods are disclosed for improving the process of managing and storing log data (e.g., log data files containing system or application error messages). Examples of such systems and methods are described in further detail herein, in reference to  FIGS. 2-7 . Components and functionality for log data management and storage may be configured and/or incorporated into information management systems such as those described herein in  FIGS. 1A-1H . 
     With the increasing importance of protecting and leveraging data, organizations simply cannot afford to take the risk of losing critical data. Moreover, runaway data growth and other modern realities make protecting and managing data an increasingly difficult task. There is therefore a need for efficient, powerful, and user-friendly solutions for protecting and managing data. 
     Depending on the size of the organization, there are typically many data production sources which are under the purview of tens, hundreds, or even thousands of employees or other individuals. In the past, individual employees were sometimes responsible for managing and protecting their data. A patchwork of hardware and software point solutions has been applied in other cases. These solutions were often provided by different vendors and had limited or no interoperability. 
     Certain embodiments described herein provide systems and methods capable of addressing these and other shortcomings of prior approaches by implementing unified, organization-wide information management.  FIG. 1A  shows one such information management system  100 , which generally includes combinations of hardware and software configured to protect and manage data and metadata, which is generated and used by the various computing devices in information management system  100 . The organization that employs the information management system  100  may be a corporation or other business entity, non-profit organization, educational institution, household, governmental agency, or the like. 
     Generally, the systems and associated components described herein may be compatible with and/or provide some or all of the functionality of the systems and corresponding components described in one or more of the following U.S. patents and patent application publications assigned to CommVault Systems, Inc., each of which is hereby incorporated in its entirety by reference herein:
         U.S. Pat. No. 7,035,880, entitled “Modular Backup and Retrieval System Used in Conjunction With a Storage Area Network”;   U.S. Pat. No. 7,107,298, entitled “System And Method For Archiving Objects In An Information Store”;   U.S. Pat. No. 7,246,207, entitled “System and Method for Dynamically Performing Storage Operations in a Computer Network”;   U.S. Pat. No. 7,315,923, entitled “System And Method For Combining Data Streams In Pipelined Storage Operations In A Storage Network”;   U.S. Pat. No. 7,343,453, entitled “Hierarchical Systems and Methods for Providing a Unified View of Storage Information”;   U.S. Pat. No. 7,395,282, entitled “Hierarchical Backup and Retrieval System”;   U.S. Pat. No. 7,529,782, entitled “System and Methods for Performing a Snapshot and for Restoring Data”;   U.S. Pat. No. 7,617,262, entitled “System and Methods for Monitoring Application Data in a Data Replication System”;   U.S. Pat. No. 7,747,579, entitled “Metabase for Facilitating Data Classification”;   U.S. Pat. No. 8,156,086, entitled “Systems And Methods For Stored Data Verification”;   U.S. Pat. No. 8,170,995, entitled “Method and System for Offline Indexing of Content and Classifying Stored Data”;   U.S. Pat. No. 8,229,954, entitled “Managing Copies Of Data”;   U.S. Pat. No. 8,230,195, entitled “System And Method For Performing Auxiliary Storage Operations”;   U.S. Pat. No. 8,285,681, entitled “Data Object Store and Server for a Cloud Storage Environment, Including Data Deduplication and Data Management Across Multiple Cloud Storage Sites”;   U.S. Pat. No. 8,307,177, entitled “Systems And Methods For Management Of Virtualization Data”;   U.S. Pat. No. 8,364,652, entitled “Content-Aligned, Block-Based Deduplication”;   U.S. Pat. No. 8,578,120, entitled “Block-Level Single Instancing”;   U.S. Pat. Pub. No. 2006/0224846, entitled “System and Method to Support Single Instance Storage Operations”;   U.S. Pat. Pub. No. 2009/0319534, entitled “Application-Aware and Remote Single Instance Data Management”;   U.S. Pat. Pub. No. 2012/0150818, entitled “Client-Side Repository in a Networked Deduplicated Storage System”; and   U.S. Pat. Pub. No. 2012/0150826, entitled “Distributed Deduplicated Storage System”.       

     The information management system  100  can include a variety of different computing devices. For instance, as will be described in greater detail herein, the information management system  100  can include one or more client computing devices  102  and secondary storage computing devices  106 . 
     Computing devices can include, without limitation, one or more: workstations, personal computers, desktop computers, or other types of generally fixed computing systems such as mainframe computers and minicomputers. Other computing devices can include mobile or portable computing devices, such as one or more laptops, tablet computers, personal data assistants, mobile phones (such as smartphones), and other mobile or portable computing devices such as embedded computers, set top boxes, vehicle-mounted devices, wearable computers, etc. Computing devices can include servers, such as mail servers, file servers, database servers, and web servers. 
     In some cases, a computing device includes virtualized and/or cloud computing resources. For instance, one or more virtual machines may be provided to the organization by a third-party cloud service vendor. Or, in some embodiments, computing devices can include one or more virtual machine(s) running on a physical host computing device (or “host machine”) operated by the organization. As one example, the organization may use one virtual machine as a database server and another virtual machine as a mail server, both virtual machines operating on the same host machine. 
     A virtual machine includes an operating system and associated virtual resources, and is hosted simultaneously with another operating system on a physical host computer (or host machine). A hypervisor (typically software, and also known in the art as a virtual machine monitor or a virtual machine manager or “VMM”) sits between the virtual machine and the hardware of the physical host machine. One example of hypervisor as virtualization software is ESX Server, by VMware, Inc. of Palo Alto, Calif.; other examples include Microsoft Virtual Server and Microsoft Windows Server Hyper-V, both by Microsoft Corporation of Redmond, Wash., and Sun xVM by Oracle America Inc. of Santa Clara, Calif. In some embodiments, the hypervisor may be firmware or hardware or a combination of software and/or firmware and/or hardware. 
     The hypervisor provides to each virtual operating system virtual resources, such as a virtual processor, virtual memory, a virtual network device, and a virtual disk. Each virtual machine has one or more virtual disks. The hypervisor typically stores the data of virtual disks in files on the file system of the physical host machine, called virtual machine disk files (in the case of VMware virtual servers) or virtual hard disk image files (in the case of Microsoft virtual servers). For example, VMware&#39;s ESX Server provides the Virtual Machine File System (VMFS) for the storage of virtual machine disk files. A virtual machine reads data from and writes data to its virtual disk much the same way that an actual physical machine reads data from and writes data to an actual disk. 
     Examples of techniques for implementing information management techniques in a cloud computing environment are described in U.S. Pat. No. 8,285,681, which is incorporated by reference herein. Examples of techniques for implementing information management techniques in a virtualized computing environment are described in U.S. Pat. No. 8,307,177, also incorporated by reference herein. 
     The information management system  100  can also include a variety of storage devices, including primary storage devices  104  and secondary storage devices  108 , for example. Storage devices can generally be of any suitable type including, without limitation, disk drives, hard-disk arrays, semiconductor memory (e.g., solid state storage devices), network attached storage (NAS) devices, tape libraries or other magnetic, non-tape storage devices, optical media storage devices, DNA/RNA-based memory technology, combinations of the same, and the like. In some embodiments, storage devices can form part of a distributed file system. In some cases, storage devices are provided in a cloud (e.g., a private cloud or one operated by a third-party vendor). A storage device in some cases comprises a disk array or portion thereof. 
     The illustrated information management system  100  includes one or more client computing device  102  having at least one application  110  executing thereon, and one or more primary storage devices  104  storing primary data  112 . The client computing device(s)  102  and the primary storage devices  104  may generally be referred to in some cases as a primary storage subsystem  117 . A computing device in an information management system  100  that has a data agent  142  installed and operating on it is generally referred to as a client computing device  102  (or, in the context of a component of the information management system  100  simply as a “client”). 
     Depending on the context, the term “information management system” can refer to generally all of the illustrated hardware and software components. Or, in other instances, the term may refer to only a subset of the illustrated components. 
     For instance, in some cases, the information management system  100  generally refers to a combination of specialized components used to protect, move, manage, manipulate, analyze, and/or process data and metadata generated by the client computing devices  102 . However, the information management system  100  in some cases does not include the underlying components that generate and/or store the primary data  112 , such as the client computing devices  102  themselves, the applications  110  and operating system operating on the client computing devices  102 , and the primary storage devices  104 . As an example, “information management system” may sometimes refer to one or more of the following components and corresponding data structures: storage managers, data agents, and media agents. These components will be described in further detail below. 
     Client Computing Devices 
     There are typically a variety of sources in an organization that produce data to be protected and managed. As just one illustrative example, in a corporate environment such data sources can be employee workstations and company servers such as a mail server, a web server, a database server, a transaction server, or the like. In the information management system  100 , the data generation sources include the one or more client computing devices  102 . 
     The client computing devices  102  may include any of the types of computing devices described above, without limitation, and in some cases the client computing devices  102  are associated with one or more users and/or corresponding user accounts, of employees or other individuals. 
     The information management system  100  generally addresses and handles the data management and protection needs for the data generated by the client computing devices  102 . However, the use of this term does not imply that the client computing devices  102  cannot be “servers” in other respects. For instance, a particular client computing device  102  may act as a server with respect to other devices, such as other client computing devices  102 . As just a few examples, the client computing devices  102  can include mail servers, file servers, database servers, and web servers. 
     Each client computing device  102  may have one or more applications  110  (e.g., software applications) executing thereon which generate and manipulate the data that is to be protected from loss and managed. The applications  110  generally facilitate the operations of an organization (or multiple affiliated organizations), and can include, without limitation, mail server applications (e.g., Microsoft Exchange Server), file server applications, mail client applications (e.g., Microsoft Exchange Client), database applications (e.g., SQL, Oracle, SAP, Lotus Notes Database), word processing applications (e.g., Microsoft Word), spreadsheet applications, financial applications, presentation applications, graphics and/or video applications, browser applications, mobile applications, entertainment applications, and so on. 
     The client computing devices  102  can have at least one operating system (e.g., Microsoft Windows, Mac OS X, iOS, IBM z/OS, Linux, other Unix-based operating systems, etc.) installed thereon, which may support or host one or more file systems and other applications  110 . 
     The client computing devices  102  and other components in information management system  100  can be connected to one another via one or more communication pathways  114 . For example, a first communication pathway  114  may connect (or communicatively couple) client computing device  102  and secondary storage computing device  106 ; a second communication pathway  114  may connect storage manager  140  and client computing device  102 ; and a third communication pathway  114  may connect storage manager  140  and secondary storage computing device  106 , etc. (see, e.g.,  FIG. 1A  and  FIG. 1C ). The communication pathways  114  can include one or more networks or other connection types including one or more of the following, without limitation: the Internet, a wide area network (WAN), a local area network (LAN), a Storage Area Network (SAN), a Fibre Channel connection, a Small Computer System Interface (SCSI) connection, a virtual private network (VPN), a token ring or TCP/IP based network, an intranet network, a point-to-point link, a cellular network, a wireless data transmission system, a two-way cable system, an interactive kiosk network, a satellite network, a broadband network, a baseband network, a neural network, a mesh network, an ad hoc network, other appropriate wired, wireless, or partially wired/wireless computer or telecommunications networks, combinations of the same or the like. The communication pathways  114  in some cases may also include application programming interfaces (APIs) including, e.g., cloud service provider APIs, virtual machine management APIs, and hosted service provider APIs. The underlying infrastructure of communication paths  114  may be wired and/or wireless, analog and/or digital, or any combination thereof; and the facilities used may be private, public, third-party provided, or any combination thereof, without limitation. 
     Primary Data and Exemplary Primary Storage Devices 
     Primary data  112  according to some embodiments is production data or other “live” data generated by the operating system and/or applications  110  operating on a client computing device  102 . The primary data  112  is generally stored on the primary storage device(s)  104  and is organized via a file system supported by the client computing device  102 . For instance, the client computing device(s)  102  and corresponding applications  110  may create, access, modify, write, delete, and otherwise use primary data  112 . In some cases, some or all of the primary data  112  can be stored in cloud storage resources (e.g., primary storage device  104  may be a cloud-based resource). 
     Primary data  112  is generally in the native format of the source application  110 . According to certain aspects, primary data  112  is an initial or first (e.g., created before any other copies or before at least one other copy) stored copy of data generated by the source application  110 . Primary data  112  in some cases is created substantially directly from data generated by the corresponding source applications  110 . 
     The primary storage devices  104  storing the primary data  112  may be relatively fast and/or expensive technology (e.g., a disk drive, a hard-disk array, solid state memory, etc.). In addition, primary data  112  may be highly changeable and/or may be intended for relatively short term retention (e.g., hours, days, or weeks). 
     According to some embodiments, the client computing device  102  can access primary data  112  from the primary storage device  104  by making conventional file system calls via the operating system. Primary data  112  may include structured data (e.g., database files), unstructured data (e.g., documents), and/or semi-structured data. Some specific examples are described below with respect to  FIG. 1B . 
     It can be useful in performing certain tasks to organize the primary data  112  into units of different granularities. In general, primary data  112  can include files, directories, file system volumes, data blocks, extents, or any other hierarchies or organizations of data objects. As used herein, a “data object” can refer to both (1) any file that is currently addressable by a file system or that was previously addressable by the file system (e.g., an archive file) and (2) a subset of such a file (e.g., a data block). 
     As will be described in further detail, it can also be useful in performing certain functions of the information management system  100  to access and modify metadata within the primary data  112 . Metadata generally includes information about data objects or characteristics associated with the data objects. For simplicity herein, it is to be understood that, unless expressly stated otherwise, any reference to primary data  112  generally also includes its associated metadata, but references to the metadata do not include the primary data. 
     Metadata can include, without limitation, one or more of the following: the data owner (e.g., the client or user that generates the data), the last modified time (e.g., the time of the most recent modification of the data object), a data object name (e.g., a file name), a data object size (e.g., a number of bytes of data), information about the content (e.g., an indication as to the existence of a particular search term), user-supplied tags, to/from information for email (e.g., an email sender, recipient, etc.), creation date, file type (e.g., format or application type), last accessed time, application type (e.g., type of application that generated the data object), location/network (e.g., a current, past or future location of the data object and network pathways to/from the data object), geographic location (e.g., GPS coordinates), frequency of change (e.g., a period in which the data object is modified), business unit (e.g., a group or department that generates, manages or is otherwise associated with the data object), aging information (e.g., a schedule, such as a time period, in which the data object is migrated to secondary or long term storage), boot sectors, partition layouts, file location within a file folder directory structure, user permissions, owners, groups, access control lists [ACLs]), system metadata (e.g., registry information), combinations of the same or other similar information related to the data object. 
     In addition to metadata generated by or related to file systems and operating systems, some of the applications  110  and/or other components of the information management system  100  maintain indices of metadata for data objects, e.g., metadata associated with individual email messages. Thus, each data object may be associated with corresponding metadata. The use of metadata to perform classification and other functions is described in greater detail below. 
     Each of the client computing devices  102  are generally associated with and/or in communication with one or more of the primary storage devices  104  storing corresponding primary data  112 . A client computing device  102  may be considered to be “associated with” or “in communication with” a primary storage device  104  if it is capable of one or more of: routing and/or storing data (e.g., primary data  112 ) to the particular primary storage device  104 , coordinating the routing and/or storing of data to the particular primary storage device  104 , retrieving data from the particular primary storage device  104 , coordinating the retrieval of data from the particular primary storage device  104 , and modifying and/or deleting data retrieved from the particular primary storage device  104 . 
     The primary storage devices  104  can include any of the different types of storage devices described above, or some other kind of suitable storage device. The primary storage devices  104  may have relatively fast I/O times and/or are relatively expensive in comparison to the secondary storage devices  108 . For example, the information management system  100  may generally regularly access data and metadata stored on primary storage devices  104 , whereas data and metadata stored on the secondary storage devices  108  is accessed relatively less frequently. 
     Primary storage device  104  may be dedicated or shared. In some cases, each primary storage device  104  is dedicated to an associated client computing device  102 . For instance, a primary storage device  104  in one embodiment is a local disk drive of a corresponding client computing device  102 . In other cases, one or more primary storage devices  104  can be shared by multiple client computing devices  102 , e.g., via a network such as in a cloud storage implementation. As one example, a primary storage device  104  can be a disk array shared by a group of client computing devices  102 , such as one of the following types of disk arrays: EMC Clariion, EMC Symmetrix, EMC Celerra, Dell EqualLogic, IBM XIV, NetApp FAS, HP EVA, and HP 3PAR. 
     The information management system  100  may also include hosted services (not shown), which may be hosted in some cases by an entity other than the organization that employs the other components of the information management system  100 . For instance, the hosted services may be provided by various online service providers to the organization. Such service providers can provide services including social networking services, hosted email services, or hosted productivity applications or other hosted applications). Hosted services may include software-as-a-service (SaaS), platform-as-a-service (PaaS), application service providers (ASPs), cloud services, or other mechanisms for delivering functionality via a network. As it provides services to users, each hosted service may generate additional data and metadata under management of the information management system  100 , e.g., as primary data  112 . In some cases, the hosted services may be accessed using one of the applications  110 . As an example, a hosted mail service may be accessed via browser running on a client computing device  102 . The hosted services may be implemented in a variety of computing environments. In some cases, they are implemented in an environment having a similar arrangement to the information management system  100 , where various physical and logical components are distributed over a network. 
     Secondary Copies and Exemplary Secondary Storage Devices 
     The primary data  112  stored on the primary storage devices  104  may be compromised in some cases, such as when an employee deliberately or accidentally deletes or overwrites primary data  112  during their normal course of work. Or the primary storage devices  104  can be damaged, lost, or otherwise corrupted. For recovery and/or regulatory compliance purposes, it is therefore useful to generate copies of the primary data  112 . Accordingly, the information management system  100  includes one or more secondary storage computing devices  106  and one or more secondary storage devices  108  configured to create and store one or more secondary copies  116  of the primary data  112  and associated metadata. The secondary storage computing devices  106  and the secondary storage devices  108  may sometimes be referred to as a secondary storage subsystem  118 . 
     Creation of secondary copies  116  can help in search and analysis efforts and meet other information management goals, such as: restoring data and/or metadata if an original version (e.g., of primary data  112 ) is lost (e.g., by deletion, corruption, or disaster); allowing point-in-time recovery; complying with regulatory data retention and electronic discovery (e-discovery) requirements; reducing utilized storage capacity; facilitating organization and search of data; improving user access to data files across multiple computing devices and/or hosted services; and implementing data retention policies. 
     The client computing devices  102  access or receive primary data  112  and communicate the data, e.g., over one or more communication pathways  114 , for storage in the secondary storage device(s)  108 . 
     A secondary copy  116  can comprise a separate stored copy of application data that is derived from one or more earlier-created, stored copies (e.g., derived from primary data  112  or another secondary copy  116 ). Secondary copies  116  can include point-in-time data, and may be intended for relatively long-term retention (e.g., weeks, months or years), before some or all of the data is moved to other storage or is discarded. 
     In some cases, a secondary copy  116  is a copy of application data created and stored subsequent to at least one other stored instance (e.g., subsequent to corresponding primary data  112  or to another secondary copy  116 ), in a different storage device than at least one previous stored copy, and/or remotely from at least one previous stored copy. In some other cases, secondary copies can be stored in the same storage device as primary data  112  and/or other previously stored copies. For example, in one embodiment a disk array capable of performing hardware snapshots stores primary data  112  and creates and stores hardware snapshots of the primary data  112  as secondary copies  116 . Secondary copies  116  may be stored in relatively slow and/or low cost storage (e.g., magnetic tape). A secondary copy  116  may be stored in a backup or archive format, or in some other format different than the native source application format or other primary data format. 
     In some cases, secondary copies  116  are indexed so users can browse and restore at another point in time. After creation of a secondary copy  116  representative of certain primary data  112 , a pointer or other location indicia (e.g., a stub) may be placed in primary data  112 , or be otherwise associated with primary data  112  to indicate the current location on the secondary storage device(s)  108  of secondary copy  116 . 
     Since an instance of a data object or metadata in primary data  112  may change over time as it is modified by an application  110  (or hosted service or the operating system), the information management system  100  may create and manage multiple secondary copies  116  of a particular data object or metadata, each representing the state of the data object in primary data  112  at a particular point in time. Moreover, since an instance of a data object in primary data  112  may eventually be deleted from the primary storage device  104  and the file system, the information management system  100  may continue to manage point-in-time representations of that data object, even though the instance in primary data  112  no longer exists. 
     For virtualized computing devices the operating system and other applications  110  of the client computing device(s)  102  may execute within or under the management of virtualization software (e.g., a VMM), and the primary storage device(s)  104  may comprise a virtual disk created on a physical storage device. The information management system  100  may create secondary copies  116  of the files or other data objects in a virtual disk file and/or secondary copies  116  of the entire virtual disk file itself (e.g., of an entire .vmdk file). 
     Secondary copies  116  may be distinguished from corresponding primary data  112  in a variety of ways, some of which will now be described. First, as discussed, secondary copies  116  can be stored in a different format (e.g., backup, archive, or other non-native format) than primary data  112 . For this or other reasons, secondary copies  116  may not be directly usable by the applications  110  of the client computing device  102 , e.g., via standard system calls or otherwise without modification, processing, or other intervention by the information management system  100 . 
     Secondary copies  116  are also in some embodiments stored on a secondary storage device  108  that is inaccessible to the applications  110  running on the client computing devices  102  (and/or hosted services). Some secondary copies  116  may be “offline copies,” in that they are not readily available (e.g., not mounted to tape or disk). Offline copies can include copies of data that the information management system  100  can access without human intervention (e.g., tapes within an automated tape library, but not yet mounted in a drive), and copies that the information management system  100  can access only with at least some human intervention (e.g., tapes located at an offsite storage site). 
     The Use of Intermediate Devices for Creating Secondary Copies 
     Creating secondary copies can be a challenging task. For instance, there can be hundreds or thousands of client computing devices  102  continually generating large volumes of primary data  112  to be protected. Also, there can be significant overhead involved in the creation of secondary copies  116 . Moreover, secondary storage devices  108  may be special purpose components, and interacting with them can require specialized intelligence. 
     In some cases, the client computing devices  102  interact directly with the secondary storage device  108  to create the secondary copies  116 . However, in view of the factors described above, this approach can negatively impact the ability of the client computing devices  102  to serve the applications  110  and produce primary data  112 . Further, the client computing devices  102  may not be optimized for interaction with the secondary storage devices  108 . 
     Thus, in some embodiments, the information management system  100  includes one or more software and/or hardware components which generally act as intermediaries between the client computing devices  102  and the secondary storage devices  108 . In addition to off-loading certain responsibilities from the client computing devices  102 , these intermediate components can provide other benefits. For instance, as discussed further below with respect to  FIG. 1D , distributing some of the work involved in creating secondary copies  116  can enhance scalability. 
     The intermediate components can include one or more secondary storage computing devices  106  as shown in  FIG. 1A  and/or one or more media agents, which can be software modules operating on corresponding secondary storage computing devices  106  (or other appropriate computing devices). Media agents are discussed below (e.g., with respect to  FIGS. 1C-1E ). 
     The secondary storage computing device(s)  106  can comprise any of the computing devices described above, without limitation. In some cases, the secondary storage computing device(s)  106  include specialized hardware and/or software componentry for interacting with the secondary storage devices  108 . 
     To create a secondary copy  116  involving the copying of data from the primary storage subsystem  117  to the secondary storage subsystem  118 , the client computing device  102  in some embodiments communicates the primary data  112  to be copied (or a processed version thereof) to the designated secondary storage computing device  106 , via the communication pathway  114 . The secondary storage computing device  106  in turn conveys the received data (or a processed version thereof) to the secondary storage device  108 . In some such configurations, the communication pathway  114  between the client computing device  102  and the secondary storage computing device  106  comprises a portion of a LAN, WAN or SAN. In other cases, at least some client computing devices  102  communicate directly with the secondary storage devices  108  (e.g., via Fibre Channel or SCSI connections). In some other cases, one or more secondary copies  116  are created from existing secondary copies, such as in the case of an auxiliary copy operation, described in greater detail below. 
     Exemplary Primary Data and an Exemplary Secondary Copy 
       FIG. 1B  is a detailed view showing some specific examples of primary data stored on the primary storage device(s)  104  and secondary copy data stored on the secondary storage device(s)  108 , with other components in the system removed for the purposes of illustration. Stored on the primary storage device(s)  104  are primary data objects including word processing documents  119 A-B, spreadsheets  120 , presentation documents  122 , video files  124 , image files  126 , email mailboxes  128  (and corresponding email messages  129 A-C), html/xml or other types of markup language files  130 , databases  132  and corresponding tables or other data structures  133 A- 133 C). 
     Some or all primary data objects are associated with corresponding metadata (e.g., “Meta 1 - 11 ”), which may include file system metadata and/or application specific metadata. Stored on the secondary storage device(s)  108  are secondary copy data objects  134 A-C which may include copies of or otherwise represent corresponding primary data objects and metadata. 
     As shown, the secondary copy data objects  134 A-C can individually represent more than one primary data object. For example, secondary copy data object  134 A represents three separate primary data objects  133 C,  122 , and  129 C (represented as  133 C′,  122 ′, and  129 C′, respectively, and accompanied by the corresponding metadata Meta 11  , Meta 3 , and Meta 8 , respectively). Moreover, as indicated by the prime mark (′), a secondary copy object may store a representation of a primary data object and/or metadata differently than the original format, e.g., in a compressed, encrypted, deduplicated, or other modified format. Likewise, secondary data object  1346  represents primary data objects  120 ,  1336 , and  119 A as  120 ′,  1336 ′, and  119 A′, respectively and accompanied by corresponding metadata Meta 2 , Meta 10 , and Meta 1 , respectively. Also, secondary data object  134 C represents primary data objects  133 A,  1196 , and  129 A as  133 A′,  1196 ′, and  129 A′, respectively, accompanied by corresponding metadata Meta 9 , Meta 5 , and Meta 6 , respectively. 
     Exemplary Information Management System Architecture 
     The information management system  100  can incorporate a variety of different hardware and software components, which can in turn be organized with respect to one another in many different configurations, depending on the embodiment. There are critical design choices involved in specifying the functional responsibilities of the components and the role of each component in the information management system  100 . For instance, as will be discussed, such design choices can impact performance as well as the adaptability of the information management system  100  to data growth or other changing circumstances. 
       FIG. 1C  shows an information management system  100  designed according to these considerations and which includes: storage manager  140 , a centralized storage and/or information manager that is configured to perform certain control functions, one or more data agents  142  executing on the client computing device(s)  102  configured to process primary data  112 , and one or more media agents  144  executing on the one or more secondary storage computing devices  106  for performing tasks involving the secondary storage devices  108 . While distributing functionality amongst multiple computing devices can have certain advantages, in other contexts it can be beneficial to consolidate functionality on the same computing device. As such, in various other embodiments, one or more of the components shown in  FIG. 1C  as being implemented on separate computing devices are implemented on the same computing device. In one configuration, a storage manager  140 , one or more data agents  142 , and one or more media agents  144  are all implemented on the same computing device. In another embodiment, one or more data agents  142  and one or more media agents  144  are implemented on the same computing device, while the storage manager  140  is implemented on a separate computing device, etc. without limitation. 
     Storage Manager 
     As noted, the number of components in the information management system  100  and the amount of data under management can be quite large. Managing the components and data is therefore a significant task, and a task that can grow in an often unpredictable fashion as the quantity of components and data scale to meet the needs of the organization. For these and other reasons, according to certain embodiments, responsibility for controlling the information management system  100 , or at least a significant portion of that responsibility, is allocated to the storage manager  140 . By distributing control functionality in this manner, the storage manager  140  can be adapted independently according to changing circumstances. Moreover, a computing device for hosting the storage manager  140  can be selected to best suit the functions of the storage manager  140 . These and other advantages are described in further detail below with respect to  FIG. 1D . 
     The storage manager  140  may be a software module or other application, which, in some embodiments operates in conjunction with one or more associated data structures, e.g., a dedicated database (e.g., management database  146 ). In some embodiments, storage manager  140  is a computing device comprising circuitry for executing computer instructions and performs the functions described herein. The storage manager generally initiates, performs, coordinates and/or controls storage and other information management operations performed by the information management system  100 , e.g., to protect and control the primary data  112  and secondary copies  116  of data and metadata. In general, storage manager  100  may be said to manage information management system  100 , which includes managing the constituent components, e.g., data agents and media agents, etc. 
     As shown by the dashed arrowed lines  114  in  FIG. 1C , the storage manager  140  may communicate with and/or control some or all elements of the information management system  100 , such as the data agents  142  and media agents  144 . Thus, in certain embodiments, control information originates from the storage manager  140  and status reporting is transmitted to storage manager  140  by the various managed components, whereas payload data and payload metadata is generally communicated between the data agents  142  and the media agents  144  (or otherwise between the client computing device(s)  102  and the secondary storage computing device(s)  106 ), e.g., at the direction of and under the management of the storage manager  140 . Control information can generally include parameters and instructions for carrying out information management operations, such as, without limitation, instructions to perform a task associated with an operation, timing information specifying when to initiate a task associated with an operation, data path information specifying what components to communicate with or access in carrying out an operation, and the like. Payload data, on the other hand, can include the actual data involved in the storage operation, such as content data written to a secondary storage device  108  in a secondary copy operation. Payload metadata can include any of the types of metadata described herein, and may be written to a storage device along with the payload content data (e.g., in the form of a header). 
     In other embodiments, some information management operations are controlled by other components in the information management system  100  (e.g., the media agent(s)  144  or data agent(s)  142 ), instead of or in combination with the storage manager  140 . 
     According to certain embodiments, the storage manager  140  provides one or more of the following functions:
         initiating execution of secondary copy operations;   managing secondary storage devices  108  and inventory/capacity of the same;   reporting, searching, and/or classification of data in the information management system  100 ;   allocating secondary storage devices  108  for secondary storage operations;   monitoring completion of and providing status reporting related to secondary storage operations;   tracking age information relating to secondary copies  116 , secondary storage devices  108 , and comparing the age information against retention guidelines;   tracking movement of data within the information management system  100 ;   tracking logical associations between components in the information management system  100 ;   protecting metadata associated with the information management system  100 ; and   implementing operations management functionality.       

     The storage manager  140  may maintain a database  146  (or “storage manager database  146 ” or “management database  146 ”) of management-related data and information management policies  148 . The database  146  may include a management index  150  (or “index  150 ”) or other data structure that stores logical associations between components of the system, user preferences and/or profiles (e.g., preferences regarding encryption, compression, or deduplication of primary or secondary copy data, preferences regarding the scheduling, type, or other aspects of primary or secondary copy or other operations, mappings of particular information management users or user accounts to certain computing devices or other components, etc.), management tasks, media containerization, or other useful data. For example, the storage manager  140  may use the index  150  to track logical associations between media agents  144  and secondary storage devices  108  and/or movement of data from primary storage devices  104  to secondary storage devices  108 . For instance, the index  150  may store data associating a client computing device  102  with a particular media agent  144  and/or secondary storage device  108 , as specified in an information management policy  148  (e.g., a storage policy, which is defined in more detail below). 
     Administrators and other people may be able to configure and initiate certain information management operations on an individual basis. But while this may be acceptable for some recovery operations or other relatively less frequent tasks, it is often not workable for implementing on-going organization-wide data protection and management. Thus, the information management system  100  may utilize information management policies  148  for specifying and executing information management operations (e.g., on an automated basis). Generally, an information management policy  148  can include a data structure or other information source that specifies a set of parameters (e.g., criteria and rules) associated with storage or other information management operations. 
     The storage manager database  146  may maintain the information management policies  148  and associated data, although the information management policies  148  can be stored in any appropriate location. For instance, an information management policy  148  such as a storage policy may be stored as metadata in a media agent database  152  or in a secondary storage device  108  (e.g., as an archive copy) for use in restore operations or other information management operations, depending on the embodiment. Information management policies  148  are described further below. 
     According to certain embodiments, the storage manager database  146  comprises a relational database (e.g., an SQL database) for tracking metadata, such as metadata associated with secondary copy operations (e.g., what client computing devices  102  and corresponding data were protected). This and other metadata may additionally be stored in other locations, such as at the secondary storage computing devices  106  or on the secondary storage devices  108 , allowing data recovery without the use of the storage manager  140  in some cases. 
     As shown, the storage manager  140  may include a jobs agent  156 , a user interface  158 , and a management agent  154 , all of which may be implemented as interconnected software modules or application programs. 
     The jobs agent  156  in some embodiments initiates, controls, and/or monitors the status of some or all storage or other information management operations previously performed, currently being performed, or scheduled to be performed by the information management system  100 . For instance, the jobs agent  156  may access information management policies  148  to determine when and how to initiate and control secondary copy and other information management operations, as will be discussed further. 
     The user interface  158  may include information processing and display software, such as a graphical user interface (“GUI”), an application program interface (“API”), or other interactive interface(s) through which users and system processes can retrieve information about the status of information management operations (e.g., storage operations) or issue instructions to the information management system  100  and its constituent components. Via the user interface  158 , users may optionally issue instructions to the components in the information management system  100  regarding performance of storage and recovery operations. For example, a user may modify a schedule concerning the number of pending secondary copy operations. As another example, a user may employ the GUI to view the status of pending storage operations or to monitor the status of certain components in the information management system  100  (e.g., the amount of capacity left in a storage device). 
     An “information management cell” (or “storage operation cell” or “cell”) may generally include a logical and/or physical grouping of a combination of hardware and software components associated with performing information management operations on electronic data, typically one storage manager  140  and at least one client computing device  102  (comprising data agent(s)  142 ) and at least one media agent  144 . For instance, the components shown in  FIG. 1C  may together form an information management cell. Multiple cells may be organized hierarchically. With this configuration, cells may inherit properties from hierarchically superior cells or be controlled by other cells in the hierarchy (automatically or otherwise). Alternatively, in some embodiments, cells may inherit or otherwise be associated with information management policies, preferences, information management metrics, or other properties or characteristics according to their relative position in a hierarchy of cells. Cells may also be delineated and/or organized hierarchically according to function, geography, architectural considerations, or other factors useful or desirable in performing information management operations. A first cell may represent a geographic segment of an enterprise, such as a Chicago office, and a second cell may represent a different geographic segment, such as a New York office. Other cells may represent departments within a particular office. Where delineated by function, a first cell may perform one or more first types of information management operations (e.g., one or more first types of secondary or other copies), and a second cell may perform one or more second types of information management operations (e.g., one or more second types of secondary or other copies). 
     The storage manager  140  may also track information that permits it to select, designate, or otherwise identify content indices, deduplication databases, or similar databases or resources or data sets within its information management cell (or another cell) to be searched in response to certain queries. Such queries may be entered by the user via interaction with the user interface  158 . In general, the management agent  154  allows multiple information management cells to communicate with one another. For example, the information management system  100  in some cases may be one information management cell of a network of multiple cells adjacent to one another or otherwise logically related in a WAN or LAN. With this arrangement, the cells may be connected to one another through respective management agents  154 . 
     For instance, the management agent  154  can provide the storage manager  140  with the ability to communicate with other components within the information management system  100  (and/or other cells within a larger information management system) via network protocols and application programming interfaces (“APIs”) including, e.g., HTTP, HTTPS, FTP, REST, virtualization software APIs, cloud service provider APIs, and hosted service provider APIs. Inter-cell communication and hierarchy is described in greater detail in e.g., U.S. Pat. Nos. 7,747,579 and 7,343,453, which are incorporated by reference herein. 
     Data Agents 
     As discussed, a variety of different types of applications  110  can operate on a given client computing device  102 , including operating systems, database applications, e-mail applications, and virtual machines, just to name a few. And, as part of the process of creating and restoring secondary copies  116 , the client computing devices  102  may be tasked with processing and preparing the primary data  112  from these various different applications  110 . Moreover, the nature of the processing/preparation can differ across clients and application types, e.g., due to inherent structural and formatting differences among applications  110 . 
     The one or more data agent(s)  142  are therefore advantageously configured in some embodiments to assist in the performance of information management operations based on the type of data that is being protected, at a client-specific and/or application-specific level. 
     The data agent  142  may be a software module or component that is generally responsible for managing, initiating, or otherwise assisting in the performance of information management operations in information management system  100 , generally as directed by storage manager  140 . For instance, the data agent  142  may take part in performing data storage operations such as the copying, archiving, migrating, and/or replicating of primary data  112  stored in the primary storage device(s)  104 . The data agent  142  may receive control information from the storage manager  140 , such as commands to transfer copies of data objects, metadata, and other payload data to the media agents  144 . 
     In some embodiments, a data agent  142  may be distributed between the client computing device  102  and storage manager  140  (and any other intermediate components) or may be deployed from a remote location or its functions approximated by a remote process that performs some or all of the functions of data agent  142 . In addition, a data agent  142  may perform some functions provided by a media agent  144 , or may perform other functions such as encryption and deduplication. 
     As indicated, each data agent  142  may be specialized for a particular application  110 , and the system can employ multiple application-specific data agents  142 , each of which may perform information management operations (e.g., perform backup, migration, and data recovery) associated with a different application  110 . For instance, different individual data agents  142  may be designed to handle Microsoft Exchange data, Lotus Notes data, Microsoft Windows file system data, Microsoft Active Directory Objects data, SQL Server data, SharePoint data, Oracle database data, SAP database data, virtual machines and/or associated data, and other types of data. 
     A file system data agent, for example, may handle data files and/or other file system information. If a client computing device  102  has two or more types of data, a specialized data agent  142  may be used for each data type to copy, archive, migrate, and restore the client computing device  102  data. For example, to backup, migrate, and/or restore all of the data on a Microsoft Exchange server, the client computing device  102  may use a Microsoft Exchange Mailbox data agent  142  to back up the Exchange mailboxes, a Microsoft Exchange Database data agent  142  to back up the Exchange databases, a Microsoft Exchange Public Folder data agent  142  to back up the Exchange Public Folders, and a Microsoft Windows File System data agent  142  to back up the file system of the client computing device  102 . In such embodiments, these specialized data agents  142  may be treated as four separate data agents  142  even though they operate on the same client computing device  102 . 
     Other embodiments may employ one or more generic data agents  142  that can handle and process data from two or more different applications  110 , or that can handle and process multiple data types, instead of or in addition to using specialized data agents  142 . For example, one generic data agent  142  may be used to back up, migrate and restore Microsoft Exchange Mailbox data and Microsoft Exchange Database data while another generic data agent may handle Microsoft Exchange Public Folder data and Microsoft Windows File System data. 
     Each data agent  142  may be configured to access data and/or metadata stored in the primary storage device(s)  104  associated with the data agent  142  and process the data as appropriate. For example, during a secondary copy operation, the data agent  142  may arrange or assemble the data and metadata into one or more files having a certain format (e.g., a particular backup or archive format) before transferring the file(s) to a media agent  144  or other component. The file(s) may include a list of files or other metadata. Each data agent  142  can also assist in restoring data or metadata to primary storage devices  104  from a secondary copy  116 . For instance, the data agent  142  may operate in conjunction with the storage manager  140  and one or more of the media agents  144  to restore data from secondary storage device(s)  108 . 
     Media Agents 
     As indicated above with respect to  FIG. 1A , off-loading certain responsibilities from the client computing devices  102  to intermediate components such as the media agent(s)  144  can provide a number of benefits including improved client computing device  102  operation, faster secondary copy operation performance, and enhanced scalability. In one specific example which will be discussed below in further detail, the media agent  144  can act as a local cache of copied data and/or metadata that it has stored to the secondary storage device(s)  108 , providing improved restore capabilities. 
     Generally speaking, a media agent  144  may be implemented as a software module that manages, coordinates, and facilitates the transmission of data, as directed by the storage manager  140 , between a client computing device  102  and one or more secondary storage devices  108 . Whereas the storage manager  140  controls the operation of the information management system  100 , the media agent  144  generally provides a portal to secondary storage devices  108 . For instance, other components in the system interact with the media agents  144  to gain access to data stored on the secondary storage devices  108 , whether it be for the purposes of reading, writing, modifying, or deleting data. Moreover, as will be described further, media agents  144  can generate and store information relating to characteristics of the stored data and/or metadata, or can generate and store other types of information that generally provides insight into the contents of the secondary storage devices  108 . 
     Media agents  144  can comprise separate nodes in the information management system  100  (e.g., nodes that are separate from the client computing devices  102 , storage manager  140 , and/or secondary storage devices  108 ). In general, a node within the information management system  100  can be a logically and/or physically separate component, and in some cases is a component that is individually addressable or otherwise identifiable. In addition, each media agent  144  may operate on a dedicated secondary storage computing device  106  in some cases, while in other embodiments a plurality of media agents  144  operate on the same secondary storage computing device  106 . 
     A media agent  144  (and corresponding media agent database  152 ) may be considered to be “associated with” a particular secondary storage device  108  if that media agent  144  is capable of one or more of: routing and/or storing data to the particular secondary storage device  108 , coordinating the routing and/or storing of data to the particular secondary storage device  108 , retrieving data from the particular secondary storage device  108 , coordinating the retrieval of data from a particular secondary storage device  108 , and modifying and/or deleting data retrieved from the particular secondary storage device  108 . 
     While media agent(s)  144  are generally associated with one or more secondary storage devices  108 , one or more media agents  144  in certain embodiments are physically separate from the secondary storage devices  108 . For instance, the media agents  144  may operate on secondary storage computing devices  106  having different housings or packages than the secondary storage devices  108 . In one example, a media agent  144  operates on a first server computer and is in communication with a secondary storage device(s)  108  operating in a separate, rack-mounted RAID-based system. 
     Where the information management system  100  includes multiple media agents  144  (see, e.g.,  FIG. 1D ), a first media agent  144  may provide failover functionality for a second, failed media agent  144 . In addition, media agents  144  can be dynamically selected for storage operations to provide load balancing. Failover and load balancing are described in greater detail below. 
     In operation, a media agent  144  associated with a particular secondary storage device  108  may instruct the secondary storage device  108  to perform an information management operation. For instance, a media agent  144  may instruct a tape library to use a robotic arm or other retrieval means to load or eject a certain storage media, and to subsequently archive, migrate, or retrieve data to or from that media, e.g., for the purpose of restoring the data to a client computing device  102 . As another example, a secondary storage device  108  may include an array of hard disk drives or solid state drives organized in a RAID configuration, and the media agent  144  may forward a logical unit number (LUN) and other appropriate information to the array, which uses the received information to execute the desired storage operation. The media agent  144  may communicate with a secondary storage device  108  via a suitable communications link, such as a SCSI or Fiber Channel link. 
     As shown, each media agent  144  may maintain an associated media agent database  152 . The media agent database  152  may be stored in a disk or other storage device (not shown) that is local to the secondary storage computing device  106  on which the media agent  144  operates. In other cases, the media agent database  152  is stored remotely from the secondary storage computing device  106 . 
     The media agent database  152  can include, among other things, an index  153  (see, e.g.,  FIG. 1C ), which comprises information generated during secondary copy operations and other storage or information management operations. The index  153  provides a media agent  144  or other component with a fast and efficient mechanism for locating secondary copies  116  or other data stored in the secondary storage devices  108 . In some cases, the index  153  does not form a part of and is instead separate from the media agent database  152 . 
     A media agent index  153  or other data structure associated with the particular media agent  144  may include information about the stored data. For instance, for each secondary copy  116 , the index  153  may include metadata such as a list of the data objects (e.g., files/subdirectories, database objects, mailbox objects, etc.), a path to the secondary copy  116  on the corresponding secondary storage device  108 , location information indicating where the data objects are stored in the secondary storage device  108 , when the data objects were created or modified, etc. Thus, the index  153  includes metadata associated with the secondary copies  116  that is readily available for use without having to be first retrieved from the secondary storage device  108 . In yet further embodiments, some or all of the information in index  153  may instead or additionally be stored along with the secondary copies of data in a secondary storage device  108 . In some embodiments, the secondary storage devices  108  can include sufficient information to perform a “bare metal restore”, where the operating system of a failed client computing device  102  or other restore target is automatically rebuilt as part of a restore operation. 
     Because the index  153  maintained in the media agent database  152  may operate as a cache, it can also be referred to as “an index cache.” In such cases, information stored in the index cache  153  typically comprises data that reflects certain particulars about storage operations that have occurred relatively recently. After some triggering event, such as after a certain period of time elapses, or the index cache  153  reaches a particular size, the index cache  153  may be copied or migrated to a secondary storage device(s)  108 . This information may need to be retrieved and uploaded back into the index cache  153  or otherwise restored to a media agent  144  to facilitate retrieval of data from the secondary storage device(s)  108 . In some embodiments, the cached information may include format or containerization information related to archives or other files stored on the storage device(s)  108 . In this manner, the index cache  153  allows for accelerated restores. 
     In some alternative embodiments the media agent  144  generally acts as a coordinator or facilitator of storage operations between client computing devices  102  and corresponding secondary storage devices  108 , but does not actually write the data to the secondary storage device  108 . For instance, the storage manager  140  (or the media agent  144 ) may instruct a client computing device  102  and secondary storage device  108  to communicate with one another directly. In such a case the client computing device  102  transmits the data directly or via one or more intermediary components to the secondary storage device  108  according to the received instructions, and vice versa. In some such cases, the media agent  144  may still receive, process, and/or maintain metadata related to the storage operations. Moreover, in these embodiments, the payload data can flow through the media agent  144  for the purposes of populating the index cache  153  maintained in the media agent database  152 , but not for writing to the secondary storage device  108 . 
     The media agent  144  and/or other components such as the storage manager  140  may in some cases incorporate additional functionality, such as data classification, content indexing, deduplication, encryption, compression, and the like. Further details regarding these and other functions are described below. 
     Distributed, Scalable Architecture 
     As described, certain functions of the information management system  100  can be distributed amongst various physical and/or logical components in the system. For instance, one or more of the storage manager  140 , data agents  142 , and media agents  144  may operate on computing devices that are physically separate from one another. This architecture can provide a number of benefits. 
     For instance, hardware and software design choices for each distributed component can be targeted to suit its particular function. The secondary computing devices  106  on which the media agents  144  operate can be tailored for interaction with associated secondary storage devices  108  and provide fast index cache operation, among other specific tasks. Similarly, the client computing device(s)  102  can be selected to effectively service the applications  110  thereon, in order to efficiently produce and store primary data  112 . 
     Moreover, in some cases, one or more of the individual components in the information management system  100  can be distributed to multiple, separate computing devices. As one example, for large file systems where the amount of data stored in the management database  146  is relatively large, the database  146  may be migrated to or otherwise reside on a specialized database server (e.g., an SQL server) separate from a server that implements the other functions of the storage manager  140 . This distributed configuration can provide added protection because the database  146  can be protected with standard database utilities (e.g., SQL log shipping or database replication) independent from other functions of the storage manager  140 . The database  146  can be efficiently replicated to a remote site for use in the event of a disaster or other data loss at the primary site. Or the database  146  can be replicated to another computing device within the same site, such as to a higher performance machine in the event that a storage manager host device can no longer service the needs of a growing information management system  100 . 
     The distributed architecture also provides both scalability and efficient component utilization.  FIG. 1D  shows an embodiment of the information management system  100  including a plurality of client computing devices  102  and associated data agents  142  as well as a plurality of secondary storage computing devices  106  and associated media agents  144 . 
     Additional components can be added or subtracted based on the evolving needs of the information management system  100 . For instance, depending on where bottlenecks are identified, administrators can add additional client computing devices  102 , secondary storage computing devices  106  (and corresponding media agents  144 ), and/or secondary storage devices  108 . Moreover, where multiple fungible components are available, load balancing can be implemented to dynamically address identified bottlenecks. As an example, the storage manager  140  may dynamically select which media agents  144  and/or secondary storage devices  108  to use for storage operations based on a processing load analysis of the media agents  144  and/or secondary storage devices  108 , respectively. 
     Moreover, each client computing device  102  in some embodiments can communicate with, among other components, any of the media agents  144 , e.g., as directed by the storage manager  140 . And each media agent  144  may be able to communicate with, among other components, any of the secondary storage devices  108 , e.g., as directed by the storage manager  140 . Thus, operations can be routed to the secondary storage devices  108  in a dynamic and highly flexible manner, to provide load balancing, failover, and the like. Further examples of scalable systems capable of dynamic storage operations, and of systems capable of performing load balancing and fail over are provided in U.S. Pat. No. 7,246,207, which is incorporated by reference herein. 
     In alternative configurations, certain components are not distributed and may instead reside and execute on the same computing device. For example, in some embodiments, one or more data agents  142  and the storage manager  140  operate on the same client computing device  102 . In another embodiment, one or more data agents  142  and one or more media agents  144  operate on a single computing device. 
     Exemplary Types of Information Management Operations 
     In order to protect and leverage stored data, the information management system  100  can be configured to perform a variety of information management operations. As will be described, these operations can generally include secondary copy and other data movement operations, processing and data manipulation operations, analysis, reporting, and management operations. The operations described herein may be performed on any type of computing device, e.g., between two computers connected via a LAN, to a mobile client telecommunications device connected to a server via a WLAN, to any manner of client computing device coupled to a cloud storage target, etc., without limitation. 
     Data Movement Operations 
     Data movement operations according to certain embodiments are generally operations that involve the copying or migration of data (e.g., payload data) between different locations in the information management system  100  in an original/native and/or one or more different formats. For example, data movement operations can include operations in which stored data is copied, migrated, or otherwise transferred from one or more first storage devices to one or more second storage devices, such as from primary storage device(s)  104  to secondary storage device(s)  108 , from secondary storage device(s)  108  to different secondary storage device(s)  108 , from secondary storage devices  108  to primary storage devices  104 , or from primary storage device(s)  104  to different primary storage device(s)  104 . 
     Data movement operations can include by way of example, backup operations, archive operations, information lifecycle management operations such as hierarchical storage management operations, replication operations (e.g., continuous data replication operations), snapshot operations, deduplication or single-instancing operations, auxiliary copy operations, and the like. As will be discussed, some of these operations involve the copying, migration or other movement of data, without actually creating multiple, distinct copies. Nonetheless, some or all of these operations are referred to as “copy” operations for simplicity. 
     Backup Operations 
     A backup operation creates a copy of a version of data (e.g., one or more files or other data units) in primary data  112  at a particular point in time. Each subsequent backup copy may be maintained independently of the first. Further, a backup copy in some embodiments is generally stored in a form that is different than the native format, e.g., a backup format. This can be in contrast to the version in primary data  112  from which the backup copy is derived, and which may instead be stored in a native format of the source application(s)  110 . In various cases, backup copies can be stored in a format in which the data is compressed, encrypted, deduplicated, and/or otherwise modified from the original application format. For example, a backup copy may be stored in a backup format that facilitates compression and/or efficient long-term storage. 
     Backup copies can have relatively long retention periods as compared to primary data  112 , and may be stored on media with slower retrieval times than primary data  112  and certain other types of secondary copies  116 . On the other hand, backups may have relatively shorter retention periods than some other types of secondary copies  116 , such as archive copies (described below). Backups may sometimes be stored at an offsite location. 
     Backup operations can include full backups, differential backups, incremental backups, “synthetic full” backups, and/or creating a “reference copy.” A full backup (or “standard full backup”) in some embodiments is generally a complete image of the data to be protected. However, because full backup copies can consume a relatively large amount of storage, it can be useful to use a full backup copy as a baseline and only store changes relative to the full backup copy for subsequent backup copies. 
     For instance, a differential backup operation (or cumulative incremental backup operation) tracks and stores changes that have occurred since the last full backup. Differential backups can grow quickly in size, but can provide relatively efficient restore times because a restore can be completed in some cases using only the full backup copy and the latest differential copy. 
     An incremental backup operation generally tracks and stores changes since the most recent backup copy of any type, which can greatly reduce storage utilization. In some cases, however, restore times can be relatively long in comparison to full or differential backups because completing a restore operation may involve accessing a full backup in addition to multiple incremental backups. 
     Synthetic full backups generally consolidate data without directly backing up data from the client computing device. A synthetic full backup is created from the most recent full backup (i.e., standard or synthetic) and subsequent incremental and/or differential backups. The resulting synthetic full backup is identical to what would have been created had the last backup for the subclient been a standard full backup. Unlike standard full, incremental, and differential backups, a synthetic full backup does not actually transfer data from a client computer to the backup media, because it operates as a backup consolidator. A synthetic full backup extracts the index data of each participating subclient. Using this index data and the previously backed up user data images, it builds new full backup images, one for each subclient. The new backup images consolidate the index and user data stored in the related incremental, differential, and previous full backups, in some embodiments creating an archive file at the subclient level. 
     Any of the above types of backup operations can be at the volume-level, file-level, or block-level. Volume level backup operations generally involve the copying of a data volume (e.g., a logical disk or partition) as a whole. In a file-level backup, the information management system  100  may generally track changes to individual files, and includes copies of files in the backup copy. In the case of a block-level backup, files are broken into constituent blocks, and changes are tracked at the block-level. Upon restore, the information management system  100  reassembles the blocks into files in a transparent fashion. 
     Far less data may actually be transferred and copied to the secondary storage devices  108  during a file-level copy than a volume-level copy. Likewise, a block-level copy may involve the transfer of less data than a file-level copy, resulting in faster execution times. However, restoring a relatively higher-granularity copy can result in longer restore times. For instance, when restoring a block-level copy, the process of locating constituent blocks can sometimes result in longer restore times as compared to file-level backups. Similar to backup operations, the other types of secondary copy operations described herein can also be implemented at either the volume-level, file-level, or block-level. 
     For example, in some embodiments, a reference copy may comprise copy(ies) of selected objects from backed up data, typically to help organize data by keeping contextual information from multiple sources together, and/or help retain specific data for a longer period of time, such as for legal hold needs. A reference copy generally maintains data integrity, and when the data is restored, it may be viewed in the same format as the source data. In some embodiments, a reference copy is based on a specialized client, individual subclient and associated information management policies (e.g., storage policy, retention policy, etc.) that are administered within information management system  100 . 
     Archive Operations 
     Because backup operations generally involve maintaining a version of the copied data in primary data  112  and also maintaining backup copies in secondary storage device(s)  108 , they can consume significant storage capacity. To help reduce storage consumption, an archive operation according to certain embodiments creates a secondary copy  116  by both copying and removing source data. Or, seen another way, archive operations can involve moving some or all of the source data to the archive destination. Thus, data satisfying criteria for removal (e.g., data of a threshold age or size) may be removed from source storage. The source data may be primary data  112  or a secondary copy  116 , depending on the situation. As with backup copies, archive copies can be stored in a format in which the data is compressed, encrypted, deduplicated, and/or otherwise modified from the format of the original application or source copy. In addition, archive copies may be retained for relatively long periods of time (e.g., years) and, in some cases, are never deleted. Archive copies are generally retained for longer periods of time than backup copies, for example. In certain embodiments, archive copies may be made and kept for extended periods in order to meet compliance regulations. 
     Moreover, when primary data  112  is archived, in some cases the corresponding primary data  112  or a portion thereof is deleted when creating the archive copy. Thus, archiving can serve the purpose of freeing up space in the primary storage device(s)  104  and easing the demand on computational resources on client computing device  102 . Similarly, when a secondary copy  116  is archived, the secondary copy  116  may be deleted, and an archive copy can therefore serve the purpose of freeing up space in secondary storage device(s)  108 . In contrast, source copies often remain intact when creating backup copies. Examples of compatible data archiving operations are provided in U.S. Pat. No. 7,107,298, which is incorporated by reference herein. 
     Snapshot Operations 
     Snapshot operations can provide a relatively lightweight, efficient mechanism for protecting data. From an end-user viewpoint, a snapshot may be thought of as an “instant” image of the primary data  112  at a given point in time, and may include state and/or status information relative to an application that creates/manages the primary data  112 . In one embodiment, a snapshot may generally capture the directory structure of an object in primary data  112  such as a file or volume or other data set at a particular moment in time and may also preserve file attributes and contents. A snapshot in some cases is created relatively quickly, e.g., substantially instantly, using a minimum amount of file space, but may still function as a conventional file system backup. 
     A “hardware snapshot” (or “hardware-based snapshot”) operation can be a snapshot operation where a target storage device (e.g., a primary storage device  104  or a secondary storage device  108 ) performs the snapshot operation in a self-contained fashion, substantially independently, using hardware, firmware and/or software operating on the storage device itself. For instance, the storage device may be capable of performing snapshot operations upon request, generally without intervention or oversight from any of the other components in the information management system  100 . In this manner, hardware snapshots can off-load other components of information management system  100  from processing involved in snapshot creation and management. 
     A “software snapshot” (or “software-based snapshot”) operation, on the other hand, can be a snapshot operation in which one or more other components in information management system  100  (e.g., client computing devices  102 , data agents  142 , etc.) implement a software layer that manages the snapshot operation via interaction with the target storage device. For instance, the component executing the snapshot management software layer may derive a set of pointers and/or data that represents the snapshot. The snapshot management software layer may then transmit the same to the target storage device, along with appropriate instructions for writing the snapshot. 
     Some types of snapshots do not actually create another physical copy of all the data as it existed at the particular point in time, but may simply create pointers that are able to map files and directories to specific memory locations (e.g., to specific disk blocks) where the data resides, as it existed at the particular point in time. For example, a snapshot copy may include a set of pointers derived from the file system or from an application. In some other cases, the snapshot may be created at the block-level, such that creation of the snapshot occurs without awareness of the file system. Each pointer points to a respective stored data block, so that collectively, the set of pointers reflect the storage location and state of the data object (e.g., file(s) or volume(s) or data set(s)) at a particular point in time when the snapshot copy was created. 
     An initial snapshot may use only a small amount of disk space needed to record a mapping or other data structure representing or otherwise tracking the blocks that correspond to the current state of the file system. Additional disk space is usually required only when files and directories are modified later on. Furthermore, when files are modified, typically only the pointers which map to blocks are copied, not the blocks themselves. In some embodiments, for example in the case of “copy-on-write” snapshots, when a block changes in primary storage, the block is copied to secondary storage or cached in primary storage before the block is overwritten in primary storage, and the pointer to that block is changed to reflect the new location of that block. The snapshot mapping of file system data may also be updated to reflect the changed block(s) at that particular point in time. In some other cases, a snapshot includes a full physical copy of all or substantially all of the data represented by the snapshot. Further examples of snapshot operations are provided in U.S. Pat. No. 7,529,782, which is incorporated by reference herein. 
     A snapshot copy in many cases can be made quickly and without significantly impacting primary computing resources because large amounts of data need not be copied or moved. In some embodiments, a snapshot may exist as a virtual file system, parallel to the actual file system. Users in some cases gain read-only access to the record of files and directories of the snapshot. By electing to restore primary data  112  from a snapshot taken at a given point in time, users may also return the current file system to the state of the file system that existed when the snapshot was taken. 
     Replication Operations 
     Another type of secondary copy operation is a replication operation. Some types of secondary copies  116  are used to periodically capture images of primary data  112  at particular points in time (e.g., backups, archives, and snapshots). However, it can also be useful for recovery purposes to protect primary data  112  in a more continuous fashion, by replicating the primary data  112  substantially as changes occur. In some cases a replication copy can be a mirror copy, for instance, where changes made to primary data  112  are mirrored or substantially immediately copied to another location (e.g., to secondary storage device(s)  108 ). By copying each write operation to the replication copy, two storage systems are kept synchronized or substantially synchronized so that they are virtually identical at approximately the same time. Where entire disk volumes are mirrored, however, mirroring can require significant amount of storage space and utilizes a large amount of processing resources. 
     According to some embodiments storage operations are performed on replicated data that represents a recoverable state, or “known good state” of a particular application running on the source system. For instance, in certain embodiments, known good replication copies may be viewed as copies of primary data  112 . This feature allows the system to directly access, copy, restore, backup or otherwise manipulate the replication copies as if the data were the “live” primary data  112 . This can reduce access time, storage utilization, and impact on source applications  110 , among other benefits. Based on known good state information, the information management system  100  can replicate sections of application data that represent a recoverable state rather than rote copying of blocks of data. Examples of compatible replication operations (e.g., continuous data replication) are provided in U.S. Pat. No. 7,617,262, which is incorporated by reference herein. 
     Deduplication/Single-Instancing Operations 
     Another type of data movement operation is deduplication or single-instance storage, which is useful to reduce the amount of non-primary data. For instance, some or all of the above-described secondary storage operations can involve deduplication in some fashion. New data is read, broken down into portions (e.g., sub-file level blocks, files, etc.) of a selected granularity, compared with blocks that are already in secondary storage, and only the new blocks are stored. Blocks that already exist are represented as pointers to the already stored data. 
     In order to streamline the comparison process, the information management system  100  may calculate and/or store signatures (e.g., hashes or cryptographically unique IDs) corresponding to the individual data blocks in a database and compare the signatures instead of comparing entire data blocks. In some cases, only a single instance of each element is stored, and deduplication operations may therefore be referred to interchangeably as “single-instancing” operations. Depending on the implementation, however, deduplication or single-instancing operations can store more than one instance of certain data blocks, but nonetheless significantly reduce data redundancy. Depending on the embodiment, deduplication blocks can be of fixed or variable length. Using variable length blocks can provide enhanced deduplication by responding to changes in the data stream, but can involve complex processing. In some cases, the information management system  100  utilizes a technique for dynamically aligning deduplication blocks (e.g., fixed-length blocks) based on changing content in the data stream, as described in U.S. Pat. No. 8,364,652, which is incorporated by reference herein. 
     The information management system  100  can perform deduplication in a variety of manners at a variety of locations in the information management system  100 . For instance, in some embodiments, the information management system  100  implements “target-side” deduplication by deduplicating data (e.g., secondary copies  116 ) stored in the secondary storage devices  108 . In some such cases, the media agents  144  are generally configured to manage the deduplication process. For instance, one or more of the media agents  144  maintain a corresponding deduplication database that stores deduplication information (e.g., datablock signatures). Examples of such a configuration are provided in U.S. Pat. Pub. No. 2012/0150826, which is incorporated by reference herein. Instead of or in combination with “target-side” deduplication, deduplication can also be performed on the “source-side” (or “client-side”), e.g., to reduce the amount of traffic between the media agents  144  and the client computing device(s)  102  and/or reduce redundant data stored in the primary storage devices  104 . According to various implementations, one or more of the storage devices of the target-side and/or source-side of an operation can be cloud-based storage devices. Thus, the target-side and/or source-side deduplication can be cloud-based deduplication. In particular, as discussed previously, the storage manager  140  may communicate with other components within the information management system  100  via network protocols and cloud service provider APIs to facilitate cloud-based deduplication/single instancing. Examples of such deduplication techniques are provided in U.S. Pat. Pub. No. 2012/0150818, which is incorporated by reference herein. Some other compatible deduplication/single instancing techniques are described in U.S. Pat. Pub. Nos. 2006/0224846 and 2009/0319534, which are incorporated by reference herein. 
     Information Lifecycle Management and Hierarchical Storage Management Operations 
     In some embodiments, files and other data over their lifetime move from more expensive, quick access storage to less expensive, slower access storage. Operations associated with moving data through various tiers of storage are sometimes referred to as information lifecycle management (ILM) operations. 
     One type of ILM operation is a hierarchical storage management (HSM) operation. A HSM operation is generally an operation for automatically moving data between classes of storage devices, such as between high-cost and low-cost storage devices. For instance, an HSM operation may involve movement of data from primary storage devices  104  to secondary storage devices  108 , or between tiers of secondary storage devices  108 . With each tier, the storage devices may be progressively relatively cheaper, have relatively slower access/restore times, etc. For example, movement of data between tiers may occur as data becomes less important over time. 
     In some embodiments, an HSM operation is similar to an archive operation in that creating an HSM copy may (though not always) involve deleting some of the source data, e.g., according to one or more criteria related to the source data. For example, an HSM copy may include data from primary data  112  or a secondary copy  116  that is larger than a given size threshold or older than a given age threshold and that is stored in a backup format. 
     Often, and unlike some types of archive copies, HSM data that is removed or aged from the source is replaced by a logical reference pointer or stub. The reference pointer or stub can be stored in the primary storage device  104  (or other source storage device, such as a secondary storage device  108 ) to replace the deleted source data and to point to or otherwise indicate the new location in a secondary storage device  108 . 
     According to one example, files are generally moved between higher and lower cost storage depending on how often the files are accessed. When a user requests access to the HSM data that has been removed or migrated, the information management system  100  uses the stub to locate the data and may make recovery of the data appear transparent, even though the HSM data may be stored at a location different from other source data. In this manner, the data appears to the user (e.g., in file system browsing windows and the like) as if it still resides in the source location (e.g., in a primary storage device  104 ). The stub may also include some metadata associated with the corresponding data, so that a file system and/or application can provide some information about the data object and/or a limited-functionality version (e.g., a preview) of the data object. 
     An HSM copy may be stored in a format other than the native application format (e.g., where the data is compressed, encrypted, deduplicated, and/or otherwise modified from the original native application format). In some cases, copies which involve the removal of data from source storage and the maintenance of stub or other logical reference information on source storage may be referred to generally as “on-line archive copies”. On the other hand, copies which involve the removal of data from source storage without the maintenance of stub or other logical reference information on source storage may be referred to as “off-line archive copies”. Examples of HSM and ILM techniques are provided in U.S. Pat. No. 7,343,453, which is incorporated by reference herein. 
     Auxiliary Copy and Disaster Recovery Operations 
     An auxiliary copy is generally a copy operation in which a copy is created of an existing secondary copy  116 . For instance, an initial secondary copy  116  may be generated using or otherwise be derived from primary data  112  (or other data residing in the secondary storage subsystem  118 ), whereas an auxiliary copy is generated from the initial secondary copy  116 . Auxiliary copies can be used to create additional standby copies of data and may reside on different secondary storage devices  108  than the initial secondary copies  116 . Thus, auxiliary copies can be used for recovery purposes if initial secondary copies  116  become unavailable. Exemplary compatible auxiliary copy techniques are described in further detail in U.S. Pat. No. 8,230,195, which is incorporated by reference herein. 
     The information management system  100  may also perform disaster recovery operations that make or retain disaster recovery copies, often as secondary, high-availability disk copies. The information management system  100  may create secondary disk copies and store the copies at disaster recovery locations using auxiliary copy or replication operations, such as continuous data replication technologies. Depending on the particular data protection goals, disaster recovery locations can be remote from the client computing devices  102  and primary storage devices  104 , remote from some or all of the secondary storage devices  108 , or both. 
     Data Analysis, Reporting, and Management Operations 
     Data analysis, reporting, and management operations can be different than data movement operations in that they do not necessarily involve the copying, migration or other transfer of data (e.g., primary data  112  or secondary copies  116 ) between different locations in the system. For instance, data analysis operations may involve processing (e.g., offline processing) or modification of already stored primary data  112  and/or secondary copies  116 . However, in some embodiments data analysis operations are performed in conjunction with data movement operations. Some data analysis operations include content indexing operations and classification operations which can be useful in leveraging the data under management to provide enhanced search and other features. Other data analysis operations such as compression and encryption can provide data reduction and security benefits, respectively. 
     Classification Operations/Content Indexing 
     In some embodiments, the information management system  100  analyzes and indexes characteristics, content, and metadata associated with the primary data  112  and/or secondary copies  116 . The content indexing can be used to identify files or other data objects having pre-defined content (e.g., user-defined keywords or phrases, other keywords/phrases that are not defined by a user, etc.), and/or metadata (e.g., email metadata such as “to”, “from”, “cc”, “bcc”, attachment name, received time, etc.). 
     The information management system  100  generally organizes and catalogues the results in a content index, which may be stored within the media agent database  152 , for example. The content index can also include the storage locations of (or pointer references to) the indexed data in the primary data  112  or secondary copies  116 , as appropriate. The results may also be stored, in the form of a content index database or otherwise, elsewhere in the information management system  100  (e.g., in the primary storage devices  104 , or in the secondary storage device  108 ). Such index data provides the storage manager  140  or another component with an efficient mechanism for locating primary data  112  and/or secondary copies  116  of data objects that match particular criteria. 
     For instance, search criteria can be specified by a user through user interface  158  of the storage manager  140 . In some cases, the information management system  100  analyzes data and/or metadata in secondary copies  116  to create an “off-line” content index, without significantly impacting the performance of the client computing devices  102 . Depending on the embodiment, the system can also implement “on-line” content indexing, e.g., of primary data  112 . Examples of compatible content indexing techniques are provided in U.S. Pat. No. 8,170,995, which is incorporated by reference herein. 
     One or more components can be configured to scan data and/or associated metadata for classification purposes to populate a database (or other data structure) of information, which can be referred to as a “data classification database” or a “metabase”. Depending on the embodiment, the data classification database(s) can be organized in a variety of different ways, including centralization, logical sub-divisions, and/or physical sub-divisions. For instance, one or more centralized data classification databases may be associated with different subsystems or tiers within the information management system  100 . As an example, there may be a first centralized metabase associated with the primary storage subsystem  117  and a second centralized metabase associated with the secondary storage subsystem  118 . In other cases, there may be one or more metabases associated with individual components, e.g., client computing devices  102  and/or media agents  144 . In some embodiments, a data classification database (metabase) may reside as one or more data structures within management database  146 , or may be otherwise associated with storage manager  140 . 
     In some cases, the metabase(s) may be included in separate database(s) and/or on separate storage device(s) from primary data  112  and/or secondary copies  116 , such that operations related to the metabase do not significantly impact performance on other components in the information management system  100 . In other cases, the metabase(s) may be stored along with primary data  112  and/or secondary copies  116 . Files or other data objects can be associated with identifiers (e.g., tag entries, etc.) in the media agent  144  (or other indices) to facilitate searches of stored data objects. Among a number of other benefits, the metabase can also allow efficient, automatic identification of files or other data objects to associate with secondary copy or other information management operations (e.g., in lieu of scanning an entire file system). Examples of compatible metabases and data classification operations are provided in U.S. Pat. Nos. 8,229,954 and 7,747,579, which are incorporated by reference herein. 
     Encryption Operations 
     The information management system  100  in some cases is configured to process data (e.g., files or other data objects, secondary copies  116 , etc.), according to an appropriate encryption algorithm (e.g., Blowfish, Advanced Encryption Standard [AES], Triple Data Encryption Standard [3-DES], etc.) to limit access and provide data security in the information management system  100 . The information management system  100  in some cases encrypts the data at the client level, such that the client computing devices  102  (e.g., the data agents  142 ) encrypt the data prior to forwarding the data to other components, e.g., before sending the data to media agents  144  during a secondary copy operation. In such cases, the client computing device  102  may maintain or have access to an encryption key or passphrase for decrypting the data upon restore. Encryption can also occur when creating copies of secondary copies, e.g., when creating auxiliary copies or archive copies. In yet further embodiments, the secondary storage devices  108  can implement built-in, high performance hardware encryption. 
     Management and Reporting Operations 
     Certain embodiments leverage the integrated, ubiquitous nature of the information management system  100  to provide useful system-wide management and reporting functions. Examples of some compatible management and reporting techniques are provided in U.S. Pat. No. 7,343,453, which is incorporated by reference herein. 
     Operations management can generally include monitoring and managing the health and performance of information management system  100  by, without limitation, performing error tracking, generating granular storage/performance metrics (e.g., job success/failure information, deduplication efficiency, etc.), generating storage modeling and costing information, and the like. As an example, a storage manager  140  or other component in the information management system  100  may analyze traffic patterns and suggest and/or automatically route data via a particular route to minimize congestion. In some embodiments, the system can generate predictions relating to storage operations or storage operation information. Such predictions, which may be based on a trending analysis, may predict various network operations or resource usage, such as network traffic levels, storage media use, use of bandwidth of communication links, use of media agent components, etc. Further examples of traffic analysis, trend analysis, prediction generation, and the like are described in U.S. Pat. No. 7,343,453, which is incorporated by reference herein. 
     In some configurations, a master storage manager  140  may track the status of storage operation cells in a hierarchy, such as the status of jobs, system components, system resources, and other items, by communicating with storage managers  140  (or other components) in the respective storage operation cells. Moreover, the master storage manager  140  may track the status of its associated storage operation cells and information management operations by receiving periodic status updates from the storage managers  140  (or other components) in the respective cells regarding jobs, system components, system resources, and other items. In some embodiments, a master storage manager  140  may store status information and other information regarding its associated storage operation cells and other system information in its index  150  (or other location). 
     The master storage manager  140  or other component may also determine whether certain storage-related criteria or other criteria are satisfied, and perform an action or trigger event (e.g., data migration) in response to the criteria being satisfied, such as where a storage threshold is met for a particular volume, or where inadequate protection exists for certain data. For instance, in some embodiments, data from one or more storage operation cells is used to dynamically and automatically mitigate recognized risks, and/or to advise users of risks or suggest actions to mitigate these risks. For example, an information management policy may specify certain requirements (e.g., that a storage device should maintain a certain amount of free space, that secondary copies should occur at a particular interval, that data should be aged and migrated to other storage after a particular period, that data on a secondary volume should always have a certain level of availability and be restorable within a given time period, that data on a secondary volume may be mirrored or otherwise migrated to a specified number of other volumes, etc.). If a risk condition or other criterion is triggered, the system may notify the user of these conditions and may suggest (or automatically implement) an action to mitigate or otherwise address the risk. For example, the system may indicate that data from a primary copy  112  should be migrated to a secondary storage device  108  to free space on the primary storage device  104 . Examples of the use of risk factors and other triggering criteria are described in U.S. Pat. No. 7,343,453, which is incorporated by reference herein. 
     In some embodiments, the system  100  may also determine whether a metric or other indication satisfies particular storage criteria and, if so, perform an action. For example, as previously described, a storage policy or other definition might indicate that a storage manager  140  should initiate a particular action if a storage metric or other indication drops below or otherwise fails to satisfy specified criteria such as a threshold of data protection. Examples of such metrics are described in U.S. Pat. No. 7,343,453, which is incorporated by reference herein. 
     In some embodiments, risk factors may be quantified into certain measurable service or risk levels for ease of comprehension. For example, certain applications and associated data may be considered to be more important by an enterprise than other data and services. Financial compliance data, for example, may be of greater importance than marketing materials, etc. Network administrators may assign priority values or “weights” to certain data and/or applications, corresponding to the relative importance. The level of compliance of storage operations specified for these applications may also be assigned a certain value. Thus, the health, impact, and overall importance of a service may be determined, such as by measuring the compliance value and calculating the product of the priority value and the compliance value to determine the “service level” and comparing it to certain operational thresholds to determine whether it is acceptable. Further examples of the service level determination are provided in U.S. Pat. No. 7,343,453, which is incorporated by reference herein. 
     The system  100  may additionally calculate data costing and data availability associated with information management operation cells according to an embodiment of the invention. For instance, data received from the cell may be used in conjunction with hardware-related information and other information about system elements to determine the cost of storage and/or the availability of particular data in the system. Exemplary information generated could include how fast a particular department is using up available storage space, how long data would take to recover over a particular system pathway from a particular secondary storage device, costs over time, etc. Moreover, in some embodiments, such information may be used to determine or predict the overall cost associated with the storage of certain information. The cost associated with hosting a certain application may be based, at least in part, on the type of media on which the data resides, for example. Storage devices may be assigned to a particular cost categories, for example. Further examples of costing techniques are described in U.S. Pat. No. 7,343,453, which is incorporated by reference herein. 
     Any of the above types of information (e.g., information related to trending, predictions, job, cell or component status, risk, service level, costing, etc.) can generally be provided to users via the user interface  158  in a single, integrated view or console (not shown). The console may support a reporting capability that allows for the generation of a variety of reports, which may be tailored to a particular aspect of information management. Report types may include: scheduling, event management, media management and data aging. Available reports may also include backup history, data aging history, auxiliary copy history, job history, library and drive, media in library, restore history, and storage policy, etc., without limitation. Such reports may be specified and created at a certain point in time as a system analysis, forecasting, or provisioning tool. Integrated reports may also be generated that illustrate storage and performance metrics, risks and storage costing information. Moreover, users may create their own reports based on specific needs. 
     The integrated user interface  158  can include an option to show a “virtual view” of the system that graphically depicts the various components in the system using appropriate icons. As one example, the user interface  158  may provide a graphical depiction of one or more primary storage devices  104 , the secondary storage devices  108 , data agents  142  and/or media agents  144 , and their relationship to one another in the information management system  100 . The operations management functionality can facilitate planning and decision-making. For example, in some embodiments, a user may view the status of some or all jobs as well as the status of each component of the information management system  100 . Users may then plan and make decisions based on this data. For instance, a user may view high-level information regarding storage operations for the information management system  100 , such as job status, component status, resource status (e.g., communication pathways, etc.), and other information. The user may also drill down or use other means to obtain more detailed information regarding a particular component, job, or the like. Further examples of some reporting techniques and associated interfaces providing an integrated view of an information management system are provided in U.S. Pat. No. 7,343,453, which is incorporated by reference herein. 
     The information management system  100  can also be configured to perform system-wide e-discovery operations in some embodiments. In general, e-discovery operations provide a unified collection and search capability for data in the system, such as data stored in the secondary storage devices  108  (e.g., backups, archives, or other secondary copies  116 ). For example, the information management system  100  may construct and maintain a virtual repository for data stored in the information management system  100  that is integrated across source applications  110 , different storage device types, etc. According to some embodiments, e-discovery utilizes other techniques described herein, such as data classification and/or content indexing. 
     Information Management Policies 
     As indicated previously, an information management policy  148  can include a data structure or other information source that specifies a set of parameters (e.g., criteria and rules) associated with secondary copy and/or other information management operations. 
     One type of information management policy  148  is a storage policy. According to certain embodiments, a storage policy generally comprises a data structure or other information source that defines (or includes information sufficient to determine) a set of preferences or other criteria for performing information management operations. Storage policies can include one or more of the following items: (1) what data will be associated with the storage policy; (2) a destination to which the data will be stored; (3) datapath information specifying how the data will be communicated to the destination; (4) the type of storage operation to be performed; and (5) retention information specifying how long the data will be retained at the destination (see, e.g.,  FIG. 1E ). 
     As an illustrative example, data associated with a storage policy can be logically organized into groups. In some cases, these logical groupings can be referred to as “sub-clients”. A sub-client may represent static or dynamic associations of portions of a data volume. Sub-clients may represent mutually exclusive portions. Thus, in certain embodiments, a portion of data may be given a label and the association is stored as a static entity in an index, database or other storage location. Sub-clients may also be used as an effective administrative scheme of organizing data according to data type, department within the enterprise, storage preferences, or the like. Depending on the configuration, sub-clients can correspond to files, folders, virtual machines, databases, etc. In one exemplary scenario, an administrator may find it preferable to separate e-mail data from financial data using two different sub-clients. 
     A storage policy can define where data is stored by specifying a target or destination storage device (or group of storage devices). For instance, where the secondary storage device  108  includes a group of disk libraries, the storage policy may specify a particular disk library for storing the sub-clients associated with the policy. As another example, where the secondary storage devices  108  include one or more tape libraries, the storage policy may specify a particular tape library for storing the sub-clients associated with the storage policy, and may also specify a drive pool and a tape pool defining a group of tape drives and a group of tapes, respectively, for use in storing the sub-client data. While information in the storage policy can be statically assigned in some cases, some or all of the information in the storage policy can also be dynamically determined based on criteria, which can be set forth in the storage policy. For instance, based on such criteria, a particular destination storage device(s) (or other parameter of the storage policy) may be determined based on characteristics associated with the data involved in a particular storage operation, device availability (e.g., availability of a secondary storage device  108  or a media agent  144 ), network status and conditions (e.g., identified bottlenecks), user credentials, and the like). 
     Datapath information can also be included in the storage policy. For instance, the storage policy may specify network pathways and components to utilize when moving the data to the destination storage device(s). In some embodiments, the storage policy specifies one or more media agents  144  for conveying data associated with the storage policy between the source (e.g., one or more host client computing devices  102 ) and destination (e.g., a particular target secondary storage device  108 ). 
     A storage policy can also specify the type(s) of operations associated with the storage policy, such as a backup, archive, snapshot, auxiliary copy, or the like. Retention information can specify how long the data will be kept, depending on organizational needs (e.g., a number of days, months, years, etc.) 
     Another type of information management policy  148  is a scheduling policy, which specifies when and how often to perform operations. Scheduling parameters may specify with what frequency (e.g., hourly, weekly, daily, event-based, etc.) or under what triggering conditions secondary copy or other information management operations will take place. Scheduling policies in some cases are associated with particular components, such as particular logical groupings of data associated with a storage policy (e.g., a sub-client), client computing device  102 , and the like. In one configuration, a separate scheduling policy is maintained for particular logical groupings of data on a client computing device  102 . The scheduling policy specifies that those logical groupings are to be moved to secondary storage devices  108  every hour according to storage policies associated with the respective sub-clients. 
     When adding a new client computing device  102 , administrators can manually configure information management policies  148  and/or other settings, e.g., via the user interface  158 . However, this can be an involved process resulting in delays, and it may be desirable to begin data protection operations quickly, without awaiting human intervention. Thus, in some embodiments, the information management system  100  automatically applies a default configuration to client computing device  102 . As one example, when one or more data agent(s)  142  are installed on one or more client computing devices  102 , the installation script may register the client computing device  102  with the storage manager  140 , which in turn applies the default configuration to the new client computing device  102 . In this manner, data protection operations can begin substantially immediately. The default configuration can include a default storage policy, for example, and can specify any appropriate information sufficient to begin data protection operations. This can include a type of data protection operation, scheduling information, a target secondary storage device  108 , data path information (e.g., a particular media agent  144 ), and the like. 
     Other types of information management policies  148  are possible, including one or more audit (or security) policies. An audit policy is a set of preferences, rules and/or criteria that protect sensitive data in the information management system  100 . For example, an audit policy may define “sensitive objects” as files or objects that contain particular keywords (e.g., “confidential,” or “privileged”) and/or are associated with particular keywords (e.g., in metadata) or particular flags (e.g., in metadata identifying a document or email as personal, confidential, etc.). An audit policy may further specify rules for handling sensitive objects. As an example, an audit policy may require that a reviewer approve the transfer of any sensitive objects to a cloud storage site, and that if approval is denied for a particular sensitive object, the sensitive object should be transferred to a local primary storage device  104  instead. To facilitate this approval, the audit policy may further specify how a secondary storage computing device  106  or other system component should notify a reviewer that a sensitive object is slated for transfer. 
     Another type of information management policy  148  is a provisioning policy. A provisioning policy can include a set of preferences, priorities, rules, and/or criteria that specify how client computing devices  102  (or groups thereof) may utilize system resources, such as available storage on cloud storage and/or network bandwidth. A provisioning policy specifies, for example, data quotas for particular client computing devices  102  (e.g., a number of gigabytes that can be stored monthly, quarterly or annually). The storage manager  140  or other components may enforce the provisioning policy. For instance, the media agents  144  may enforce the policy when transferring data to secondary storage devices  108 . If a client computing device  102  exceeds a quota, a budget for the client computing device  102  (or associated department) is adjusted accordingly or an alert may trigger. 
     While the above types of information management policies  148  have been described as separate policies, one or more of these can be generally combined into a single information management policy  148 . For instance, a storage policy may also include or otherwise be associated with one or more scheduling, audit, or provisioning policies or operational parameters thereof. Moreover, while storage policies are typically associated with moving and storing data, other policies may be associated with other types of information management operations. The following is a non-exhaustive list of items the information management policies  148  may specify:
         schedules or other timing information, e.g., specifying when and/or how often to perform information management operations;   the type of copy  116  (e.g., type of secondary copy) and/or copy format (e.g., snapshot, backup, archive, HSM, etc.);   a location or a class or quality of storage for storing secondary copies  116  (e.g., one or more particular secondary storage devices  108 );   preferences regarding whether and how to encrypt, compress, deduplicate, or otherwise modify or transform secondary copies  116 ;   which system components and/or network pathways (e.g., preferred media agents  144 ) should be used to perform secondary storage operations;   resource allocation among different computing devices or other system components used in performing information management operations (e.g., bandwidth allocation, available storage capacity, etc.);   whether and how to synchronize or otherwise distribute files or other data objects across multiple computing devices or hosted services; and   retention information specifying the length of time primary data  112  and/or secondary copies  116  should be retained, e.g., in a particular class or tier of storage devices, or within the information management system  100 .       

     Policies can additionally specify or depend on a variety of historical or current criteria that may be used to determine which rules to apply to a particular data object, system component, or information management operation, such as:
         frequency with which primary data  112  or a secondary copy  116  of a data object or metadata has been or is predicted to be used, accessed, or modified;   time-related factors (e.g., aging information such as time since the creation or modification of a data object);   deduplication information (e.g., hashes, data blocks, deduplication block size, deduplication efficiency or other metrics);   an estimated or historic usage or cost associated with different components (e.g., with secondary storage devices  108 );   the identity of users, applications  110 , client computing devices  102  and/or other computing devices that created, accessed, modified, or otherwise utilized primary data  112  or secondary copies  116 ;   a relative sensitivity (e.g., confidentiality, importance) of a data object, e.g., as determined by its content and/or metadata;   the current or historical storage capacity of various storage devices;   the current or historical network capacity of network pathways connecting various components within the storage operation cell;   access control lists or other security information; and   the content of a particular data object (e.g., its textual content) or of metadata associated with the data object.
 
Exemplary Storage Policy and Secondary Storage Operations
       

       FIG. 1E  includes a data flow diagram depicting performance of storage operations by an embodiment of an information management system  100 , according to an exemplary storage policy  148 A. The information management system  100  includes a storage manger  140 , a client computing device  102  having a file system data agent  142 A and an email data agent  142 B operating thereon, a primary storage device  104 , two media agents  144 A,  144 B, and two secondary storage devices  108 A,  108 B: a disk library  108 A and a tape library  108 B. As shown, the primary storage device  104  includes primary data  112 A, which is associated with a logical grouping of data associated with a file system, and primary data  112 B, which is associated with a logical grouping of data associated with email. Although for simplicity the logical grouping of data associated with the file system is referred to as a file system sub-client, and the logical grouping of data associated with the email is referred to as an email sub-client, the techniques described with respect to  FIG. 1E  can be utilized in conjunction with data that is organized in a variety of other manners. 
     As indicated by the dashed box, the second media agent  144 B and the tape library  108 B are “off-site”, and may therefore be remotely located from the other components in the information management system  100  (e.g., in a different city, office building, etc.). Indeed, “off-site” may refer to a magnetic tape located in storage, which must be manually retrieved and loaded into a tape drive to be read. In this manner, information stored on the tape library  108 B may provide protection in the event of a disaster or other failure. 
     The file system sub-client and its associated primary data  112 A in certain embodiments generally comprise information generated by the file system and/or operating system of the client computing device  102 , and can include, for example, file system data (e.g., regular files, file tables, mount points, etc.), operating system data (e.g., registries, event logs, etc.), and the like. The e-mail sub-client, on the other hand, and its associated primary data  112 B, include data generated by an e-mail application operating on the client computing device  102 , and can include mailbox information, folder information, emails, attachments, associated database information, and the like. As described above, the sub-clients can be logical containers, and the data included in the corresponding primary data  112 A,  112 B may or may not be stored contiguously. 
     The exemplary storage policy  148 A includes backup copy preferences (or rule set)  160 , disaster recovery copy preferences rule set  162 , and compliance copy preferences or rule set  164 . The backup copy rule set  160  specifies that it is associated with a file system sub-client  166  and an email sub-client  168 . Each of these sub-clients  166 ,  168  are associated with the particular client computing device  102 . The backup copy rule set  160  further specifies that the backup operation will be written to the disk library  108 A, and designates a particular media agent  144 A to convey the data to the disk library  108 A. Finally, the backup copy rule set  160  specifies that backup copies created according to the rule set  160  are scheduled to be generated on an hourly basis and to be retained for 30 days. In some other embodiments, scheduling information is not included in the storage policy  148 A, and is instead specified by a separate scheduling policy. 
     The disaster recovery copy rule set  162  is associated with the same two sub-clients  166 ,  168 . However, the disaster recovery copy rule set  162  is associated with the tape library  108 B, unlike the backup copy rule set  160 . Moreover, the disaster recovery copy rule set  162  specifies that a different media agent, namely  144 B, will be used to convey the data to the tape library  108 B. As indicated, disaster recovery copies created according to the rule set  162  will be retained for 60 days, and will be generated on a daily basis. Disaster recovery copies generated according to the disaster recovery copy rule set  162  can provide protection in the event of a disaster or other catastrophic data loss that would affect the backup copy  116 A maintained on the disk library  108 A. 
     The compliance copy rule set  164  is only associated with the email sub-client  168 , and not the file system sub-client  166 . Compliance copies generated according to the compliance copy rule set  164  will therefore not include primary data  112 A from the file system sub-client  166 . For instance, the organization may be under an obligation to store and maintain copies of email data for a particular period of time (e.g., 10 years) to comply with state or federal regulations, while similar regulations do not apply to the file system data. The compliance copy rule set  164  is associated with the same tape library  108 B and media agent  144 B as the disaster recovery copy rule set  162 , although a different storage device or media agent could be used in other embodiments. Finally, the compliance copy rule set  164  specifies that copies generated under the compliance copy rule set  164  will be retained for 10 years, and will be generated on a quarterly basis. 
     At step  1 , the storage manager  140  initiates a backup operation according to the backup copy rule set  160 . For instance, a scheduling service running on the storage manager  140  accesses scheduling information from the backup copy rule set  160  or a separate scheduling policy associated with the client computing device  102 , and initiates a backup copy operation on an hourly basis. Thus, at the scheduled time slot the storage manager  140  sends instructions to the client computing device  102  (i.e., to both data agent  142 A and data agent  142 B) to begin the backup operation. 
     At step  2 , the file system data agent  142 A and the email data agent  142 B operating on the client computing device  102  respond to the instructions received from the storage manager  140  by accessing and processing the primary data  112 A,  112 B involved in the copy operation, which can be found in primary storage device  104 . Because the operation is a backup copy operation, the data agent(s)  142 A,  142 B may format the data into a backup format or otherwise process the data. 
     At step  3 , the client computing device  102  communicates the retrieved, processed data to the first media agent  144 A, as directed by the storage manager  140 , according to the backup copy rule set  160 . In some other embodiments, the information management system  100  may implement a load-balancing, availability-based, or other appropriate algorithm to select from the available set of media agents  144 A,  144 B. Regardless of the manner the media agent  144 A is selected, the storage manager  140  may further keep a record in the storage manager database  146  of the association between the selected media agent  144 A and the client computing device  102  and/or between the selected media agent  144 A and the backup copy  116 A. 
     The target media agent  144 A receives the data from the client computing device  102 , and at step  4  conveys the data to the disk library  108 A to create the backup copy  116 A, again at the direction of the storage manager  140  and according to the backup copy rule set  160 . The secondary storage device  108 A can be selected in other ways. For instance, the media agent  144 A may have a dedicated association with a particular secondary storage device(s), or the storage manager  140  or media agent  144 A may select from a plurality of secondary storage devices, e.g., according to availability, using one of the techniques described in U.S. Pat. No. 7,246,207, which is incorporated by reference herein. 
     The media agent  144 A can also update its index  153  to include data and/or metadata related to the backup copy  116 A, such as information indicating where the backup copy  116 A resides on the disk library  108 A, data and metadata for cache retrieval, etc. The storage manager  140  may similarly update its index  150  to include information relating to the storage operation, such as information relating to the type of storage operation, a physical location associated with one or more copies created by the storage operation, the time the storage operation was performed, status information relating to the storage operation, the components involved in the storage operation, and the like. In some cases, the storage manager  140  may update its index  150  to include some or all of the information stored in the index  153  of the media agent  144 A. After the 30 day retention period expires, the storage manager  140  instructs the media agent  144 A to delete the backup copy  116 A from the disk library  108 A. Indexes  150  and/or  153  are updated accordingly. 
     At step  5 , the storage manager  140  initiates the creation of a disaster recovery copy  116 B according to the disaster recovery copy rule set  162 . 
     At step  6 , illustratively based on the instructions received from the storage manager  140  at step  5 , the specified media agent  144 B retrieves the most recent backup copy  116 A from the disk library  108 A. 
     At step  7 , again at the direction of the storage manager  140  and as specified in the disaster recovery copy rule set  162 , the media agent  144 B uses the retrieved data to create a disaster recovery copy  116 B on the tape library  108 B. In some cases, the disaster recovery copy  116 B is a direct, mirror copy of the backup copy  116 A, and remains in the backup format. In other embodiments, the disaster recovery copy  116 B may be generated in some other manner, such as by using the primary data  112 A,  112 B from the primary storage device  104  as source data. The disaster recovery copy operation is initiated once a day and the disaster recovery copies  116 B are deleted after 60 days; indexes are updated accordingly when/after each information management operation is executed/completed. 
     At step  8 , the storage manager  140  initiates the creation of a compliance copy  116 C, according to the compliance copy rule set  164 . For instance, the storage manager  140  instructs the media agent  144 B to create the compliance copy  116 C on the tape library  108 B at step  9 , as specified in the compliance copy rule set  164 . In the example, the compliance copy  116 C is generated using the disaster recovery copy  116 B. In other embodiments, the compliance copy  116 C is instead generated using either the primary data  112 B corresponding to the email sub-client or using the backup copy  116 A from the disk library  108 A as source data. As specified, in the illustrated example, compliance copies  116 C are created quarterly, and are deleted after ten years, and indexes are kept up-to-date accordingly. 
     While not shown in  FIG. 1E , at some later point in time, a restore operation can be initiated involving one or more of the secondary copies  116 A,  116 B,  116 C. As one example, a user may manually initiate a restore of the backup copy  116 A by interacting with the user interface  158  of the storage manager  140 . The storage manager  140  then accesses data in its index  150  (and/or the respective storage policy  148 A) associated with the selected backup copy  116 A to identify the appropriate media agent  144 A and/or secondary storage device  108 A. 
     In other cases, a media agent may be selected for use in the restore operation based on a load balancing algorithm, an availability based algorithm, or other criteria. The selected media agent  144 A retrieves the data from the disk library  108 A. For instance, the media agent  144 A may access its index  153  to identify a location of the backup copy  116 A on the disk library  108 A, or may access location information residing on the disk  108 A itself. 
     When the backup copy  116 A was recently created or accessed, the media agent  144 A accesses a cached version of the backup copy  116 A residing in the index  153 , without having to access the disk library  108 A for some or all of the data. Once it has retrieved the backup copy  116 A, the media agent  144 A communicates the data to the source client computing device  102 . Upon receipt, the file system data agent  142 A and the email data agent  142 B may unpackage (e.g., restore from a backup format to the native application format) the data in the backup copy  116 A and restore the unpackaged data to the primary storage device  104 . 
     Exemplary Applications of Storage Policies 
     The storage manager  140  may permit a user to specify aspects of the storage policy  148 A. For example, the storage policy can be modified to include information governance policies to define how data should be managed in order to comply with a certain regulation or business objective. The various policies may be stored, for example, in the management database  146 . An information governance policy may comprise a classification policy, which is described herein. An information governance policy may align with one or more compliance tasks that are imposed by regulations or business requirements. Examples of information governance policies might include a Sarbanes-Oxley policy, a HIPAA policy, an electronic discovery (E-Discovery) policy, and so on. 
     Information governance policies allow administrators to obtain different perspectives on all of an organization&#39;s online and offline data, without the need for a dedicated data silo created solely for each different viewpoint. As described previously, the data storage systems herein build a centralized index that reflects the contents of a distributed data set that spans numerous clients and storage devices, including both primary and secondary copies, and online and offline copies. An organization may apply multiple information governance policies in a top-down manner over that unified data set and indexing schema in order to permit an organization to view and manipulate the single data set through different lenses, each of which is adapted to a particular compliance or business goal. Thus, for example, by applying an E-discovery policy and a Sarbanes-Oxley policy, two different groups of users in an organization can conduct two very different analyses of the same underlying physical set of data copies, which may be distributed throughout the organization and information management system. 
     A classification policy defines a taxonomy of classification terms or tags relevant to a compliance task and/or business objective. A classification policy may also associate a defined tag with a classification rule. A classification rule defines a particular combination of criteria, such as users who have created, accessed or modified a document or data object; file or application types; content or metadata keywords; clients or storage locations; dates of data creation and/or access; review status or other status within a workflow (e.g., reviewed or un-reviewed); modification times or types of modifications; and/or any other data attributes in any combination, without limitation. A classification rule may also be defined using other classification tags in the taxonomy. The various criteria used to define a classification rule may be combined in any suitable fashion, for example, via Boolean operators, to define a complex classification rule. As an example, an E-discovery classification policy might define a classification tag “privileged” that is associated with documents or data objects that (1) were created or modified by legal department staff, or (2) were sent to or received from outside counsel via email, or (3) contain one of the following keywords: “privileged” or “attorney” or “counsel”, or other like terms. 
     One specific type of classification tag, which may be added to an index at the time of indexing, is an entity tag. An entity tag may be, for example, any content that matches a defined data mask format. Examples of entity tags might include, e.g., social security numbers (e.g., any numerical content matching the formatting mask XXX-XX-XXXX), credit card numbers (e.g., content having a 13-16 digit string of numbers), SKU numbers, product numbers, etc. 
     A user may define a classification policy by indicating criteria, parameters or descriptors of the policy via a graphical user interface, such as a form or page with fields to be filled in, pull-down menus or entries allowing one or more of several options to be selected, buttons, sliders, hypertext links or other known user interface tools for receiving user input, etc. For example, a user may define certain entity tags, such as a particular product number or project ID code that is relevant in the organization. In some implementations, the classification policy can be implemented using cloud-based techniques. For example, the storage devices may be cloud storage devices, and the storage manager  140  may execute cloud service provider API over a network to classify data stored on cloud storage devices. 
     Exemplary Secondary Copy Formatting 
     The formatting and structure of secondary copies  116  can vary, depending on the embodiment. In some cases, secondary copies  116  are formatted as a series of logical data units or “chunks” (e.g., 512 MB, 1 GB, 2 GB, 4 GB, or 8 GB chunks). This can facilitate efficient communication and writing to secondary storage devices  108 , e.g., according to resource availability. For example, a single secondary copy  116  may be written on a chunk-by-chunk basis to a single secondary storage device  108  or across multiple secondary storage devices  108 . In some cases, users can select different chunk sizes, e.g., to improve throughput to tape storage devices. 
     Generally, each chunk can include a header and a payload. The payload can include files (or other data units) or subsets thereof included in the chunk, whereas the chunk header generally includes metadata relating to the chunk, some or all of which may be derived from the payload. For example, during a secondary copy operation, the media agent  144 , storage manager  140 , or other component may divide the associated files into chunks and generate headers for each chunk by processing the constituent files. The headers can include a variety of information such as file identifier(s), volume(s), offset(s), or other information associated with the payload data items, a chunk sequence number, etc. Importantly, in addition to being stored with the secondary copy  116  on the secondary storage device  108 , the chunk headers can also be stored to the index  153  of the associated media agent(s)  144  and/or the index  150 . This is useful in some cases for providing faster processing of secondary copies  116  during restores or other operations. In some cases, once a chunk is successfully transferred to a secondary storage device  108 , the secondary storage device  108  returns an indication of receipt, e.g., to the media agent  144  and/or storage manager  140 , which may update their respective indexes  153 ,  150  accordingly. During restore, chunks may be processed (e.g., by the media agent  144 ) according to the information in the chunk header to reassemble the files. 
     Data can also be communicated within the information management system  100  in data channels that connect the client computing devices  102  to the secondary storage devices  108 . These data channels can be referred to as “data streams”, and multiple data streams can be employed to parallelize an information management operation, improving data transfer rate, among providing other advantages. Example data formatting techniques including techniques involving data streaming, chunking, and the use of other data structures in creating copies (e.g., secondary copies) are described in U.S. Pat. Nos. 7,315,923 and 8,156,086, and 8,578,120, each of which is incorporated by reference herein. 
       FIGS. 1F and 1G  are diagrams of example data streams  170  and  171 , respectively, which may be employed for performing data storage operations. Referring to  FIG. 1F , the data agent  142  forms the data stream  170  from the data associated with a client computing device  102  (e.g., primary data  112 ). The data stream  170  is composed of multiple pairs of stream header  172  and stream data (or stream payload)  174 . The data streams  170  and  171  shown in the illustrated example are for a single-instanced storage operation, and a stream payload  174  therefore may include both single-instance (“SI”) data and/or non-SI data. A stream header  172  includes metadata about the stream payload  174 . This metadata may include, for example, a length of the stream payload  174 , an indication of whether the stream payload  174  is encrypted, an indication of whether the stream payload  174  is compressed, an archive file identifier (ID), an indication of whether the stream payload  174  is single instanceable, and an indication of whether the stream payload  174  is a start of a block of data. 
     Referring to  FIG. 1G , the data stream  171  has the stream header  172  and stream payload  174  aligned into multiple data blocks. In this example, the data blocks are of size 64 KB. The first two stream header  172  and stream payload  174  pairs comprise a first data block of size 64 KB. The first stream header  172  indicates that the length of the succeeding stream payload  174  is 63 KB and that it is the start of a data block. The next stream header  172  indicates that the succeeding stream payload  174  has a length of 1 KB and that it is not the start of a new data block. Immediately following stream payload  174  is a pair comprising an identifier header  176  and identifier data  178 . The identifier header  176  includes an indication that the succeeding identifier data  178  includes the identifier for the immediately previous data block. The identifier data  178  includes the identifier that the data agent  142  generated for the data block. The data stream  171  also includes other stream header  172  and stream payload  174  pairs, which may be for SI data and/or for non-SI data. 
       FIG. 1H  is a diagram illustrating the data structures  180  that may be used to store blocks of SI data and non-SI data on the storage device (e.g., secondary storage device  108 ). According to certain embodiments, the data structures  180  do not form part of a native file system of the storage device. The data structures  180  include one or more volume folders  182 , one or more chunk folders  184 / 185  within the volume folder  182 , and multiple files within the chunk folder  184 . Each chunk folder  184 / 185  includes a metadata file  186 / 187 , a metadata index file  188 / 189 , one or more container files  190 / 191 / 193 , and a container index file  192 / 194 . The metadata file  186 / 187  stores non-SI data blocks as well as links to SI data blocks stored in container files. The metadata index file  188 / 189  stores an index to the data in the metadata file  186 / 187 . The container files  190 / 191 / 193  store SI data blocks. The container index file  192 / 194  stores an index to the container files  190 / 191 / 193 . Among other things, the container index file  192 / 194  stores an indication of whether a corresponding block in a container file  190 / 191 / 193  is referred to by a link in a metadata file  186 / 187 . For example, data block B 2  in the container file  190  is referred to by a link in the metadata file  187  in the chunk folder  185 . Accordingly, the corresponding index entry in the container index file  192  indicates that the data block B 2  in the container file  190  is referred to. As another example, data block B 1  in the container file  191  is referred to by a link in the metadata file  187 , and so the corresponding index entry in the container index file  192  indicates that this data block is referred to. 
     As an example, the data structures  180  illustrated in  FIG. 1H  may have been created as a result of two storage operations involving two client computing devices  102 . For example, a first storage operation on a first client computing device  102  could result in the creation of the first chunk folder  184 , and a second storage operation on a second client computing device  102  could result in the creation of the second chunk folder  185 . The container files  190 / 191  in the first chunk folder  184  would contain the blocks of SI data of the first client computing device  102 . If the two client computing devices  102  have substantially similar data, the second storage operation on the data of the second client computing device  102  would result in the media agent  144  storing primarily links to the data blocks of the first client computing device  102  that are already stored in the container files  190 / 191 . Accordingly, while a first storage operation may result in storing nearly all of the data subject to the storage operation, subsequent storage operations involving similar data may result in substantial data storage space savings, because links to already stored data blocks can be stored instead of additional instances of data blocks. 
     If the operating system of the secondary storage computing device  106  on which the media agent  144  operates supports sparse files, then when the media agent  144  creates container files  190 / 191 / 193 , it can create them as sparse files. A sparse file is type of file that may include empty space (e.g., a sparse file may have real data within it, such as at the beginning of the file and/or at the end of the file, but may also have empty space in it that is not storing actual data, such as a contiguous range of bytes all having a value of zero). Having the container files  190 / 191 / 193  be sparse files allows the media agent  144  to free up space in the container files  190 / 191 / 193  when blocks of data in the container files  190 / 191 / 193  no longer need to be stored on the storage devices. In some examples, the media agent  144  creates a new container file  190 / 191 / 193  when a container file  190 / 191 / 193  either includes 100 blocks of data or when the size of the container file  190  exceeds 50 MB. In other examples, the media agent  144  creates a new container file  190 / 191 / 193  when a container file  190 / 191 / 193  satisfies other criteria (e.g., it contains from approximately 100 to approximately 1000 blocks or when its size exceeds approximately 50 MB to 1 GB). 
     In some cases, a file on which a storage operation is performed may comprise a large number of data blocks. For example, a 100 MB file may comprise 400 data blocks of size 256 KB. If such a file is to be stored, its data blocks may span more than one container file, or even more than one chunk folder. As another example, a database file of 20 GB may comprise over 40,000 data blocks of size 512 KB. If such a database file is to be stored, its data blocks will likely span multiple container files, multiple chunk folders, and potentially multiple volume folders. Restoring such files may require accessing multiple container files, chunk folders, and/or volume folders to obtain the requisite data blocks. 
     Introduction: Log Data 
     In a computing environment, various computing systems and/or applications generate log data that describes or provides information relating to the transactions executed in the computing environment. Such log data often comprises a sequence of log lines, where each log entry (also referred to herein as “log line”) includes information related to a single transaction. For example, when a user authentication system verifies a user&#39;s identity, the system may record the receipt of a user request to log in in one log line (e.g., “Received login request from User123”), the initiation of the verification process in another log line (e.g., “Initiated user verification with id:User123::pw:xSf3Fa#1”), and the result of the verification in yet another log line (e.g., “Completed verification and granted access to User123”). Such log lines may be saved in a log data file. The user managing the computing environment may access such a log data file to obtain information regarding the transactions executed in the computing environment. 
     An Exemplary System for Implementing Log Data Management Process 
       FIG. 2A  is a block diagram illustrating an exemplary system  200  configured to implement a log data management process in accordance with one or more embodiments disclosed herein. As illustrated, the exemplary system  200  includes client computing device  202 , storage manager  204 , media agent(s)  206 , and secondary storage device  208 . 
     The client computing device  202  includes an indexing agent  210  including a fingerprint calculation module  212 , an application  214 , a data agent  216 , a primary storage device  218  storing raw log data  220  and indexed log data  222 , other data agent(s)  224 , and other application(s)  226 . 
     The application  214  may be a database application, a mail application, or any other application that is configured to generate raw log data  220 , which is stored in the primary storage device  218  as shown in  FIG. 2A . The raw log data  220  may be similar to the primary data  112  described with reference to  FIGS. 1A and 1C  and may comprise the transaction log of the application  214 . The raw log data  220  is generated by the application  214  “live,” meaning that the raw log data  220  is generated as the application  214  undergoes transactions (e.g., connect to a database, receive a login attempt, modify data stored in a database, etc.) or immediately thereafter. In some embodiments, the raw log data  220  may record all transactions that the application  214  performs. In other embodiments, the raw log data  220  only comprises errors and warnings encountered during the execution of the application  214  (e.g., failed to connect to a machine, disk is almost full, etc.). 
     The indexing agent  210  may analyze the raw log data  220  generated by the application  210  and generate the indexed log data  222  based on the analysis of the raw log data  220 . Although the raw log data  220  and the indexed log data  222  are both illustrated in the example of  FIG. 2A , in some embodiments, only the indexed log data  222  may be stored. For example, the indexing agent  210  may generate the indexed log data  222  by processing the raw log data  220  generated by the application  214 . In some embodiments, the indexed log data  222  is a categorized and indexed version of the raw log data  222 . In the present disclosure, the term “indexing,” in addition to having its ordinary meaning, is used to refer to the process of transforming raw data into a format that is more readable and navigable by the viewer of such data. For example, the process may include categorizing the log entries in a log data file into a small number (e.g., 5, 10, 20, etc.) of expandable groups such that all the groups are visible to the viewer without the viewer having to scroll through a large number of log entries that are present in the log data. In one embodiment, all of such groups are visible to the viewer at the same time (e.g., without the viewer having to scroll). 
     The fingerprint calculation module  212  may generate a number of values (e.g., key, hash code, etc.) that may be used to index the log data. In the present disclosure, the term “fingerprint,” in addition to having its ordinary meaning, is used to refer to a value that is used to index the raw log data  222 . The fingerprint may be virtually unique (e.g., may uniquely identify the sequence of characters that it is associated with). For example, if the log entries that are included in the log data  222  are divided into three categories, database errors, login errors, and memory errors, the values generated by the fingerprint calculation module  212  for the log entries that belong to the database errors category may be the same (e.g., fingerprint “A”), the values generated by the fingerprint calculation module  212  for the log entries that belong to the database errors category may be the same (e.g., fingerprint “B”), and the values generated by the fingerprint calculation module  212  for the log entries that belong to the database errors category may be the same (e.g., fingerprint “C”), where fingerprints “A,” “B,” and “C” are all different from each other. In some embodiments, the log entries that belong to the same category, instead of having identical fingerprints, have fingerprints that are within a range of fingerprints. For example, the log entries that are categorized as database errors may have fingerprints ranging from 1 to 100, the log entries that are categorized as login errors may have fingerprints ranging from 101 to 200, and the log entries that are categorized as memory errors may have fingerprints ranging from 201 to 300. The details of the indexing agent  210  and the fingerprint calculation module  212  are further described below with reference to  FIGS. 3-5 . 
     The data agent  216  may be configured similar to any of the other data agents described herein to access the data stored in the primary storage device  218  and gather and process the data for back up or other data protection operations in which the data is copied onto the secondary storage device  208  as needed. In certain embodiments, the storage manager  204  may direct the data agent  216  (e.g., using the control information described above with reference to  FIG. 1D ) to perform a backup of the data stored on the primary storage device  218 . In some embodiments, the data agent  216  may be distributed between the client computing device  202  and the storage manager  204 , or may be deployed from a remote location or its functions approximated by a remote process that performs some or all of the functions of the data agent  216 . In some embodiments, the data agent  216  may comprise multiple data agents, and different individual data agents  216  may be designed to handle different types of log data, such as log data generated by different applications  214 . Each data agent  216  may be configured to access the data stored in the primary storage device  218  associated with the data agent  216  and process the data as appropriate. As shown in  FIG. 2A , in addition to the application  214  and the data agent  216 , other data agents  224  and other applications  226  may reside on the client computing device  202 , and each of the other data agents  224  may be associated with a corresponding one of the other applications  226 . 
     The client computing device  202  (or one or more components thereof) may be the same or substantially similar to the client computing device  102  (or one or more components thereof) described above with reference  FIGS. 1A-1G . For example, the client computing device  202  may further provide one or more functionalities of the client computing device  102  described above. 
     The storage manger  204  may manage and store various preferences, rules, and policies regarding storage, backup, encryption, compression, or deduplication of the data (e.g., raw log data  220  and indexed log data  222 ) stored in the primary storage device  218 . A system administrator may create, modify, and/or delete one or more log data management and storage preferences, rules, and policies via the storage manager  204 . Such log data management and storage preferences, rules, and policies may be stored in any appropriate location, such as in the storage manager  204 , the client computing device  202 , and/or the secondary storage device  208 . 
     The storage manager  204  (or one or more components thereof) may be the same or substantially similar to the storage manager  140  (or one or more components thereof) described above with reference  FIGS. 1A-1G . For example, the storage manager  204  may further provide one or more functionalities of the storage manager  140  described above. 
     The media agent(s)  206  may be implemented as a software module that manages, coordinates, and facilitates the transmission of data, as directed by the storage manager  204 , to and/or from the secondary storage device  208  (e.g., between the client computing device  202  and the secondary storage device  208 ). Although the secondary storage device  208  is shown as a single secondary storage device in the example of  FIG. 2A , it should be appreciated that any number of secondary storage devices may be used to implement the secondary storage device  208 , as described with reference to  FIG. 1D . For example, upon receiving a data backup request from the client computing device  202  or the storage manager  204 , the media agent(s)  206  may route and/or store the data (e.g., raw log data  220  and indexed log data  222 ) stored in the primary storage device  218  to the appropriate secondary storage device  208 , or modify or add to the existing copy of the data stored in the secondary storage device  208 . 
     The media agent(s)  206  (or one or more components thereof) may be the same or substantially similar to the media agent(s)  144  (or one or more components thereof) described above with reference  FIGS. 1A-1G . For example, the media agent(s)  206  may further provide one or more functionalities of the media agent(s)  144  described above. Although not shown in  FIG. 2A , the media agent(s)  206  may be implemented on the secondary storage device  208  as previously described (e.g., with respect to  FIG. 1C ). 
     The illustrated secondary storage device  208  may store data backed up from the primary storage device  218 . For example, the data stored in the secondary storage device  208  may include log data generated by the application  214 . Further, the secondary storage device  208  may communicate with components other than those illustrated in  FIG. 2A  and store data other than those described herein. 
     The secondary storage device  208  (or one or more components thereof) may be substantially the same or similar to the secondary storage device  108  (or one or more components thereof) described above with reference  FIGS. 1A-1G . For example, the secondary storage device  208  may further provide one or more functionalities of the secondary storage device  108  described above. 
     The system  200  and corresponding components of  FIG. 2A  may be similar to or the same as the system  100  and similarly named components shown in any of  FIGS. 1A-1H , where applicable, such as  FIG. 1D . Moreover, depending on the embodiment, the system  200  of  FIG. 2A  may additionally include any of the other components shown in  FIG. 1D  that are not specifically shown in  FIG. 2A . The system  200  may include one or more of each component. All components of the system  200  can be in direct communication with each other or communicate indirectly via the client computing device  202 , the storage manager  204 , the media agent(s)  206 , the secondary storage device  208 , or the like. In certain embodiments, some of the components in  FIG. 2A  shown as separate components can reside on a single computing device. Alternatively, or additionally, one or more components shown in  FIG. 2A  as residing on a single computing device can be distributed across multiple devices. 
     Another Exemplary System for Implementing Log Data Management Process 
       FIG. 2B  is a block diagram illustrating another exemplary system  250  configured to implement a log data management process in accordance with one or more embodiments disclosed herein. As illustrated, the exemplary system  250  includes client computing device  202 , storage manager  204 , media agent(s)  206 , and secondary storage device  208 . In the example of  FIG. 2B , the media agent(s)  206  includes the indexing agent  210 , and the indexing agent  210  may operate on a log data backup  230  (e.g., a backup copy of the log data generated by one or more applications operating on the client computing device  202 ). Based on the log data backup  230  stored on the secondary storage device  208 , the indexing agent  210  may generate indexed log data  232  and store the generated indexed log data  232  on the secondary storage device  208 . One or more components of the system  250  may be configured similarly as their counterpart components in the system  200  of  FIG. 2A . 
     Illustrative Routine for Processing Log Data 
       FIG. 3  is flow diagram illustrative of one embodiment of a routine  300  for indexing the raw log data generated by one or more applications executing on client computing devices. The routine  300  is described with respect to the system  200  of  FIG. 2A . However, one or more of the steps of the routine  300  may be implemented by other information management systems, such as those described in greater detail above with reference to  FIG. 1D . The routine  300  can be implemented by any one or a combination of a client computing device, an application running on the client computing device, a customized plug-in installed on the application, a storage manager, an indexing agent, a data agent, a media agent, and the like. Although the steps in the routine  300  are described as being performed by the indexing agent  210  of the system  200 , the embodiments discussed herein are not limited as such, and the steps in the routine  300  may be performed by other components of the system  200 , either alone or in combination. 
     At block  302  of the routine  300 , the indexing agent  210  receives log data generated by the application  214 . The log data may include one or more errors, warnings, events, and/or other information relating to transactions that have occurred during the execution of the application  214 . The log data may comprise a plurality of log lines that indicate the nature of the transactions (e.g., what kind of error occurred, what kind of warning was detected, etc.). For example, a log line might say, “Error: failed to connect to database DB231.” In this example, the log line indicates that an error has occurred while trying to connect to a database having an ID of “DB231”. In some embodiments, each log line may describe a single transaction. In other embodiments, a single transaction may span multiple log lines. The indexing agent  210  may receive the log data directly from the application  214 . In some embodiments, instead of receiving the log data from another component, the indexing agent  210  may access a log data file stored in the primary storage device  218  or another storage location in the system  200  such as the secondary storage device  208 . In one embodiment, the log data file is a text file that includes log data generated during the execution of the application  214 . In another embodiment, the log data file can be any file that includes information generated by the application  214 . The indexing agent  210  may periodically access the log data file and process the log data file as described below. 
     At block  304 , the indexing agent  210  processes the initial log line contained in the log data. As described above, the log data may comprise a plurality of log lines that each indicate a different transaction that occurred during the execution of the application  214 . The indexing agent  210  may process the initial log line by extracting the first line in the log data file. In some embodiments, after the initial log line is extracted, the initial log line may be removed from the log data file. Although the log data file is described herein as having a plurality of log lines, in other embodiments, the log data file may include other units such as log entries that are not necessarily separated by a new line or contained in separate lines. For example, the log entries contained in a log data file may be separated by any delimiter (e.g., a semicolon, a comma, etc.) that can be used to denote the start and/or the end of a log entry. 
     At block  306 , the indexing agent  210  extracts a static portion of the log line. Each log line may have a static portion and a variable portion. For example, if the software generating the log data encounters an error reading a file, the software may generate a log line that says, “could not read &lt;filename&gt; because of error &lt;error code&gt;.” From such a log line, name value pairs (or key value pairs) may be extracted (e.g., filename=HelloWorld.txt, error code=E28548). In some embodiments, using the name value pairs, the log lines may be indexed using the extracted name value pairs. For example, the log lines may be stored in a database with fields “filename” and “error code” that may be searchable by the user. 
     In another example, the log line may read, “EvAppMgr::lookupCommCells( )—commcellId [2], installTime [14074765333]”. From this log line, the indexing agent  210  may extract two name value pairs (e.g., commcellId=2 and installTime=14074765333). The indexing agent  210  may calculate fingerprints using the static portion of the log line (e.g., sequence of characters in the log line without the variable portion thereof). In this example, the static portion of the log line may be “EvAppMgr::lookupCommCells( )—commcellId [ ], installTime [ ]”. In some embodiments, the indexing agent  210  may index the log line with the calculated fingerprint as an additional field. 
     In yet another example, if the processed log line says “Error: failed to connect to database DB231,” the portion of the log line that says “Error: failed to connect to database” may be the static portion of the log line, and the portion of the log line that says “DB231” may be the variable portion of the log line. The static portion of the log line may be a template phrase or other alphanumeric text string that are selected by the application  214  from a pool of log templates based on the transaction that corresponds to the log line. For example, if the application  214  attempted to connect to a database but failed to do so, the application  214  may select “Error: failed to connect to database” for generating the log line corresponding to the failed attempt. In some embodiments, the static portion may be the portion of the log line that says “Error:” or “Error: failed to connect”. In other embodiments, the static portion is any portion of the log line that also appears in at least one other log line in the log data file. The log lines may contain a code that indicates the static portions of the log lines. For example, if the processed log line says, “Error#1342: failed to connect to database DB231,” the indexing agent  210  may determine the static portion of the log line to be “failed to connect to database” based on the number “1342” provided in the log line (e.g., each log line containing the string “Error#1342” may also include a static portion that says “failed to connect to database”). In some embodiments, the application  214  may indicate the static and variable portions of the log line. For example, the log data file may include indications that specify which portions are static portions and which portions are variable portions. A single log line may have multiple static portions and/or multiple variable portions. 
     In some embodiments, the indexing agent  210  may determine the static portion(s) and the variable portion(s) on the fly based on the content of the log lines processed by the indexing agent  210 . In such embodiments, the indexing agent  210  may determine the static portion(s) based on the number of times that a particular block of text has appeared in the log lines or the percentage of log lines containing a particular block of text. In one example, the indexing agent  210  may use a block of text as a static portion if the same block of text (e.g., “failed to connect to database”) has appeared in the log lines more than a threshold number of times (e.g., 5, 10, 50, 100, etc.). In another example, the indexing agent  210  may use a block of text as a static portion if the same block of text (e.g., “failed to connect to database”) has appeared in at least a threshold percentage of the log lines (e.g., 1%, 5%, 10%, 20%, etc.). In some embodiments, the indexing agent  210  determines the static portion(s) such that the number of different static portions appearing in the log lines is less than a maximum number (e.g., 5, 10, 20, etc.). For example, if the number of processed log lines is relatively small, each static portion may be more specific and include more details related to the transactions (e.g., “Error: failed to connect to database” or “Error: failed to connect to machine”). On the other hand, if the number of processed log lines is relatively large, the indexing agent  210  may be more generic and include fewer details related to the transactions (e.g., “Error” or “Error: failed to connect”). In some embodiments, the indexing agent  210  modifies the static portions and re-organizes the existing log data structure based on the modified static portions. For example, log lines that were previously categorized under “Error: failed to connect to database,” “Error: failed to connect to machine,” and “Error: failed to connect to network” may be combined into a single category of “Error: failed to connect.” By reducing the number of categories under which the log lines are categorized, the indexing agent  210  may eliminate the need for the user to browse through a prohibitively large number of categories and/or log lines and allow the user to quickly determine what kinds of transactions are being logged in the system. In some embodiments, the variable portion(s) of the log lines are indicated using predetermined characters (e.g., brackets), and the static portion(s) may comprise the portion of the log lines that are not indicated as the variable portion(s). For example, in a log line that reads, “Error: failed to connect to database [DB2184]”, the variable portion may be DB2184 and the static portion may be “Error: failed to connect to database”. In another example, in a log line that reads, “Host=192.168.1.105; Error description=incorrect password”, the static portions may be “Host” and “Error description” and the variable portions may be “192.168.1.105” and “incorrect password”. The indexing agent  210  may have access to such predetermined conventions (e.g., the variable portions appearing between brackets, the variable portions immediately following an equal sign, etc.) with which the generated log lines comply. The indexing agent  210  may retrieve such conventions from a configuration file stored in the primary storage device  218  or another storage device connected to the client computing device  202  via a network. 
     At block  308 , the indexing agent  210  calculates a fingerprint based on the extracted static portion. The fingerprint may be any value (e.g., key, hash code, etc.) that identifies the static portion. In some embodiments, the fingerprint may uniquely identify the static portion (e.g., different static portions would have different fingerprints) or virtually uniquely identify the static portion. In other embodiments, a single fingerprint may identify multiple different static portions. When different static portions are assigned the same fingerprint, the different static portions may be similar in nature (e.g., the static portions are all related to “failed to connect” errors) or similar in form (e.g. “failed to connect to machine” vs. “failed to connect to machines”). In some embodiments, two static portions that are similar or identical may have different fingerprints (e.g., “failed to connect to machine” may be assigned a fingerprint of 105 and “failed to connect to machines” may be assigned a fingerprint of 106). Such similar or identical static portions may have fingerprints that are within a predetermined threshold value. For example, fingerprints ranging from 101 to 110 may be related to “failed to connect” errors. In another example, static portions having fingerprints that are within ±10 from each other may be similar or identical. In some embodiments, static portions having fingerprints that are within a predefined range or within a threshold value from each other are categorized into the same group for the purpose of displaying the log data to a user, as described in greater detail in connection with block  318 . The process of calculating the fingerprints for the static and variable portions of the log lines is described in greater detail below with reference to  FIG. 4 . 
     At block  310 , the indexing agent  210  extracts a variable portion of the log line. The variable portion of the log line may be a portion of the log line that may vary from log line to log line, such as where two log lines sharing a common static portion have different variable portions. For example, the log data may include one log line that says, “Error: failed to connect to database DB231” and another log line that says, “Error: failed to connect to database DB717.” In this example, the variable portions may be “DB231” and “DB717,” respectively. In another example, the log data may include one log line that says, “Error: failed to connect to machine M1029” and another log line that says, “Error: failed to connect to database DB717.” In this example, the variable portions may be “machine M1029” and “database DB717.” 
     At block  312 , the indexing agent  210  determines whether it has finished processing the log data. For example, the indexing agent  210  may check whether the next character or next line comprises an end of file (EOF) character or another indication that the indexing agent  210  has processed all the log lines in the log data file. If the indexing agent  210  determines that it has finished processing the log lines, the routine  300  proceeds to block  316 . Otherwise, the routine  300  proceeds to block  314 . 
     At block  314 , the indexing agent  210  processes the next log line in the log data file, and repeats blocks  306 - 312  until the indexing agent  210  determines that it has finished processing the log lines. 
     At block  316 , the indexing agent  210  organizes the log lines contained in the log data file for presentation to the user based on the calculated fingerprints. In some embodiments, the indexing agent  210  may index the log lines based on the calculated fingerprints associated with the log lines. For example, the indexing agent  210  may index the log lines by grouping the log lines based on the static fingerprints assigned to the log lines. In one example, the log lines having the same static fingerprints (e.g., fingerprints calculated based on the static portions of the log lines) may be categorized into the same group for the purpose of displaying the log data to a user. In such an example, the static portions of the log lines that are in the same group may be identical. The data to be displayed to the user may include a list of static portions that represent the groups of log lines and the corresponding number of log lines in each group, for example, as illustrated in  FIG. 6 , which is described below in greater detail. In another example, log lines having static fingerprints that are within a predefined range or within a threshold value from each other may be categorized into the same group for the purpose of displaying the log data to a user. In some embodiments, variable fingerprints (e.g., fingerprints calculated based on the variable portions of the log lines) may optionally be calculated (e.g., between blocks  310  and  312 ) based on the variable portion(s) of the log lines and used to divide the log lines that are in a single group into one or more subgroups. For example, each error (e.g., log line) resulting from a failure to connect to a database may have a static fingerprint of 3050. There may be multiple log lines having a static fingerprint value of 3050, and each of those log lines may have resulted from a failure to connect to “Database X.” In such a case, the log lines may have the same variable fingerprint and thus be assigned to the same subgroup. In another example, one set of those log lines may have resulted from a failure to connect to “Database X” and another set of log lines may have resulted from a failure to connect to “Database Y.” In such a case, each of those two sets of log lines may have different variable fingerprints and thus be assigned to a different subgroup. Although in the routine  300 , the log lines are described as being categorized based on a static fingerprint and/or a variable fingerprint, the log lines may be categorized into multiple groups and/or subgroups based on multiple static fingerprints and/or multiple variable fingerprints. Once the log lines are organized for presentation to the user, the routine  300  ends. 
     The routine  300  can include fewer, more, or different blocks than those illustrated in  FIG. 3  without departing from the spirit and scope of the description. For example, in an alternative embodiment, block  310  may be omitted and the indexing agent  210  may categorize the log lines based on only the static fingerprint(s) of the log lines. In another alternative embodiment, blocks  306 - 310  may be modified such that the indexing agent  210  processes multiple static portions and/or multiple variable portions from the log line. It will be appreciated by those skilled in the art and others that some or all of the functions described in this disclosure may be embodied in software executed by one or more processors of the disclosed components and mobile communication devices. The software may be persistently stored in any type of non-volatile storage. 
     Illustrative Routine for Calculating a Fingerprint 
     Turning to  FIG. 4 , an example routine  400  for calculating a fingerprint is described. The routine  400  is described with respect to the system  200  of  FIG. 2A . However, one or more of the steps of the routine  400  may be implemented by other information management systems, such as those described in greater detail above with reference to  FIG. 1D . The routine  400  can be implemented by any one or a combination of a client computing device, an application running on the client computing device, a customized plug-in installed on the application, a storage manager, an indexing agent, a data agent, a media agent, and the like. Although the steps in the routine  400  are described as being performed by the indexing agent  210  of the system  200 , the embodiments discussed herein are not limited as such, and the steps in the routine  400  may be performed by other components of the system  200 , either alone or in combination. 
     At block  402  of the routine  400 , the indexing agent  210  receives the extracted portion of the log line. For example, the extracted portion may be a static portion of the log line extracted at block  306  of  FIG. 3  or a variable portion of the log line extracted at block  310  of  FIG. 3 . The extracted portion may comprise a sequence of characters, including, but not limited to, ASCII characters and symbols. 
     At block  404 , the indexing agent  210  extracts a first overlapping trigram from the extracted portion. In the present disclosure, the term “trigram,” in addition to having its ordinary meaning, is used to refer to a contiguous sequence of three characters. For example, if the extracted portion contains 5 characters (e.g., “ABCDE”), the extracted portion contains three overlapping trigrams (e.g., “ABC”, “BCD”, and “CDE”), and the first overlapping trigram of the extracted portion would be “ABC”. In some embodiments, the trigrams exclude special characters or symbols (e.g., commas, colons, semicolons, etc.). In such embodiments, if the extracted portion comprises a phrase “Error::failed”, the overlapping trigrams of the extracted portion may include “Err”, “rro”, “ror”, “orf”, “rfa”, “fai”, “ail”, “ile”, and “led”. In some embodiments, the trigrams include special characters and symbols. In such embodiments, if the extracted portion comprises a phrase “Error::failed”, the overlapping trigrams of the extracted portion may include “Err”, “rro”, “ror”, “or:”, “r::”, “::f”, “:fa”, “fai”, “ail”, “ile”, and “led”. 
     At block  406 , the indexing agent  210  calculates the value of the trigram. In some embodiments, each character in the trigram may have a corresponding assigned value, and the indexing agent  210  may calculate the value of the trigram by multiplying the assigned values assigned to the characters in the trigram. For example, if the trigram comprises “ABC” and the values assigned to “A”, “B”, and “C” are 2, 79, and 5, respectively, the value of the trigram would be 2*79*5, which is 790. In some embodiments, each character in the trigram is assigned to a different prime number. In such embodiments, the prime number assigned to a character may be based on the relative frequency of the character in the relevant language (e.g., the English language, if the character is taken from the English alphabet). For example, the most frequently appearing character (e.g., “e” in English) may be assigned the lowest prime number (e.g., 2), the second most frequently appearing character (e.g., “t” in English) may be assigned the second lowest prime number (e.g., 3), and so on. 
     At block  408 , the indexing agent  210  determines whether it has finished processing the extracted portion. If the indexing agent  210  determines that it has not finished processing the extracted portion, the routine  400  proceeds to block  410 , where the indexing agent  210  extracts the next trigram. For example, if the extracted portion is the phrase “Error,” and the indexing agent  210  has processed the first trigram “Err,” the indexing agent  210  extracts the next trigram (e.g., “rro”) and the routine  400  proceeds to block  406 . On the other hand, if the indexing agent  210  determines that it has finished processing the extracted portion, the routine  400  proceeds to block  412 . 
     At block  412 , the indexing agent  210  calculates the fingerprint of the extracted portion by summing the values calculated for the trigrams extracted from the extracted portion. For example, if the extracted portion is the phrase “Error,” the indexing agent  210  may calculate the fingerprint for the extracted portion by adding the values of the overlapping trigrams “Err”, “rro”, and “ror”, which may be 2*23*23+23*23*7+23*7*23=8464. In this example, if the extracted portion is the phrase “Rorre” (error spelled backwards), the extracted portion may also have the same fingerprint value (e.g., 23*7*23 for “Ror”, 7*23*23 for “orr”, and 23*23*2 for “rre”, the sum of which equals 8464). In some embodiments, the trigrams may be weighted differently based on the order of calculation such that a phase spelled backward (e.g., “Rorré”) has a different fingerprint value than the same phrase spelled forward (e.g., “Error”). For example, the first trigram may be multiplied by a weight of 1, the second trigram may be multiplied by a weight of 2, etc. In such an example, the phrase “Error” would have a fingerprint of (1)*(2*23*23)+(2)*(23*23*7)+(3)*(23*7*23)=19573, and the phrase “Rorre” would have a fingerprint of (1)*(23*7*23)+(2)*(7*23*23)+(3)*(23*23*2)=14283. In other embodiments, each element within a trigram may be offset based on where they are located within the trigram. For example, the first character of the trigram may be offset by 1, the second character of the trigram may be offset by 2, etc. In such an example, the phrase “Error” would have a fingerprint of (2+1)*(23+2)*(23+3)+(23+1)*(23+2)*(7+3)+(23+1)*(7+2)*(23+3)=13566, and the phrase “Rorre” would have a fingerprint of (23+1)*(7+2)*(23+3)+(7+1)*(23+2)*(23+3)+(23+1)*(23+2)*(2+3)=15816. 
     The routine  400  can include fewer, more, or different blocks than those illustrated in  FIG. 4  without departing from the spirit and scope of the description. For example, in an alternative embodiment, instead of using trigrams, the indexing agent  210  may use bigrams, 4-grams, or other groups of characters to calculate the fingerprint of the extracted portion. It will be appreciated by those skilled in the art and others that some or all of the functions described in this disclosure may be embodied in software executed by one or more processors of the disclosed components and mobile communication devices. The software may be persistently stored in any type of non-volatile storage. 
     Illustrative Routine for Monitoring Log Data 
     Turning to  FIG. 5 , an example routine  500  for monitoring the log data is described. The routine  500  is described with respect to the system  200  of  FIG. 2A . However, one or more of the steps of routine  500  may be implemented by other information management systems, such as those described in greater detail above with reference to  FIG. 1D . The routine  500  can be implemented by any one or a combination of a client computing device, an application running on the client computing device, a customized plug-in installed on the application, a storage manager, an indexing agent, a data agent, a media agent, and the like. Although the steps in the routine  500  are described as being performed by the indexing agent  210  of the system  200 , the embodiments discussed herein are not limited as such, and the steps in the routine  500  may be performed by other components of the system  200 , either alone or in combination. 
     At block  502  of the routine  500 , the indexing agent  210  monitors the processed log data. In some embodiments, the indexing agent  210  may maintain a database including the details of the log data generated in the system  200  and processed by the indexing agent  210 . Such a database may include information such as how many log lines have been processed by the indexing agent  210 , how many errors and/or warnings have been detected, how many log lines have been categorized under each fingerprint value (or static portion), etc. 
     At block  504 , the indexing agent  210  compares the processed log data to a default model. The default model may specify the expected values of the different variables monitored by the indexing agent  210 . For example, the default model may indicate how many errors the system  200  is expected to encounter, how many warnings the system  200  is expected to encounter, etc. More specifically, the default model may indicate how many database errors the system  200  is expected to encounter, how many login errors the system  200  is expected to encounter, etc. In some embodiments, the default model may comprise an aggregation of the values processed by the indexing agent  210 . For example, the default model may comprise last year&#39;s data, a 5-year running average, an average of the recorded data to date, etc. In some embodiments, the indexing agent  210  may perform the comparison of block  504  periodically. For example, the indexing agent  210  may perform the comparison after every hour, day, week, month, quarter, year, etc. In other embodiments, the indexing agent  210  may perform the comparison of block  504  after a threshold amount of log data (e.g., after every 1000 log lines) have been processed. 
     At block  506 , the indexing agent  210  determines whether any anomalies are detected. In some embodiments, the indexing agent  210  may make such a determination by determining whether the values indicated by the current log data is different from the values indicated by the default model by a threshold value or a threshold percentage. For example, if the default model indicates that 1200 errors have been encountered per year on average for the past 5 years, but the log data processed by the indexing agent  210  indicates that the system  200  has encountered 5000 errors this month, the indexing agent  210  may determine that there is something wrong with the log data processed this month since the number of errors encountered during this month is about 5000% of the monthly average indicated by the default model. If the indexing agent  210  determines that anomalies have not been detected, the routine  500  proceeds to block  502 , where the indexing agent  210  continues to monitor the processed log data. Otherwise, the routine  500  proceeds to block  508 . 
     At block  508 , the indexing agent  210  generates a report for presentation to a user (e.g., a system administrator overseeing the system  200 ). The report may indicate the anomalies detected by the indexing agent  210 . For example, the report may indicate that the number of errors exceeded the expected amount by 200%. In another example, the report may indicate that the number of login requests processed by the system  200  exceeded the expected amount by 1000%. In yet another example, the report may indicate that the system  200  has experienced an unusually high number of failures to connect to Database #1219. Once the report is generated, the routine  500  ends. 
     The routine  500  can include fewer, more, or different blocks than those illustrated in  FIG. 5  without departing from the spirit and scope of the description. For example, in an alternative embodiment, at block  508 , the indexing agent  210  may provide an indication to another component in the system  200  that one or more anomalies have been detected in the log data, and said another component may generate a report in response to receiving such an indication provided by the indexing agent  210 . In another embodiment, the report generated at block  508  may be displayed to the user or the user may receive a notification that such a report has been generated for the user&#39;s review. It will be appreciated by those skilled in the art and others that some or all of the functions described in this disclosure may be embodied in software executed by one or more processors of the disclosed components and mobile communication devices. The software may be persistently stored in any type of non-volatile storage. 
     Processing the Log Data on Backup 
     One or more embodiments of the present application are described in a way that the log data is processed as the system and/or application generates the log data (e.g., substantially concurrently as the log data is generated). However, the one or more embodiments of the present application are not limited to such a configuration, and the features and techniques described herein may instead be performed when the log data is backed up or archived. For example, the log data may be stored in a primary storage device (e.g., primary storage device  222  of  FIG. 2A ), and when the log data is backed up to a secondary storage device (e.g., secondary storage device  208  of  FIG. 2A ), the log data may be processed as described above with reference to  FIGS. 3-5 , by a media agent or storage manager, for example. In some embodiments, log data or backed up log data corresponding to multiple client computing devices is processed by a central entity, such as a storage manager. 
     Illustrative Examples of Log Data Display 
     Now a specific, illustrative example will be provided with reference to  FIGS. 6 and 7 .  FIG. 6  illustrates an example display  600  generated based on the log data processed by the indexing agent  210 .  FIG. 7  illustrates an example display  700  showing the contents of one of the groups under which the processed log lines are categorized. 
     The display  600  of  FIG. 6  shows a log breakdown, which includes six categories under which the log lines processed by the indexing agent  210  are organized. As shown in  FIG. 6 , the processed log lines include 9148 failures to connect to one or more machines, 922 failures to connect to one or more databases, 582 out-of-memory errors, 69 index-out-of-bounds errors, 7 unauthorized accesses, and 2 disk capacity warnings. The (+) sign indicates that each of the categories may be expanded to list the sub-categories therein. By reviewing the log breakdown shown in  FIG. 6 , the user can quickly determine what kind of errors and warnings (and how many of them) have been encountered in the system  200  without having to comb through the thousands of log lines processed by the indexing agent  210 . 
     The display  700  of  FIG. 7  shows 4 different sub-categories listed under the second category (“Error: failed to connect to database”). As shown in  FIG. 7 , the  950  failures to connect to one or more databases include  401  failures to connect to database DB231, 323 failures to connect to database DB717, 219 failures to connect to database DB010, and 7 failures to connect to database DB184. By reviewing the log breakdown shown in  FIG. 7 , the user can quickly determine which databases are causing problems in the system  200  without having to comb through the thousands of log lines processed by the indexing agent  210 . 
     Terminology 
     Conditional language, such as, among others, “can,” “could,” “might,” or “may,” unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain embodiments include, while other embodiments do not include, certain features, elements and/or steps. Thus, such conditional language is not generally intended to imply that features, elements and/or steps are in any way required for one or more embodiments or that one or more embodiments necessarily include logic for deciding, with or without user input or prompting, whether these features, elements and/or steps are included or are to be performed in any particular embodiment. 
     Unless the context clearly requires otherwise, throughout the description and the claims, the words “comprise,” “comprising,” and the like are to be construed in an inclusive sense, as opposed to an exclusive or exhaustive sense; that is to say, in the sense of “including, but not limited to.” As used herein, the terms “connected,” “coupled,” or any variant thereof means any connection or coupling, either direct or indirect, between two or more elements; the coupling or connection between the elements can be physical, logical, or a combination thereof. Additionally, the words “herein,” “above,” “below,” and words of similar import, when used in this application, refer to this application as a whole and not to any particular portions of this application. Where the context permits, words in the above Detailed Description using the singular or plural number may also include the plural or singular number respectively. The word “or” in reference to a list of two or more items, covers all of the following interpretations of the word: any one of the items in the list, all of the items in the list, and any combination of the items in the list. Likewise the term “and/or” in reference to a list of two or more items, covers all of the following interpretations of the word: any one of the items in the list, all of the items in the list, and any combination of the items in the list. 
     Depending on the embodiment, certain operations, acts, events, or functions of any of the algorithms described herein can be performed in a different sequence, can be added, merged, or left out altogether (e.g., not all are necessary for the practice of the algorithms). Moreover, in certain embodiments, operations, acts, functions, or events can be performed concurrently, e.g., through multi-threaded processing, interrupt processing, or multiple processors or processor cores or on other parallel architectures, rather than sequentially. 
     Systems and modules described herein may comprise software, firmware, hardware, or any combination(s) of software, firmware, or hardware suitable for the purposes described herein. Software and other modules may reside and execute on servers, workstations, personal computers, computerized tablets, PDAs, and other computing devices suitable for the purposes described herein. Software and other modules may be accessible via local memory, via a network, via a browser, or via other means suitable for the purposes described herein. Data structures described herein may comprise computer files, variables, programming arrays, programming structures, or any electronic information storage schemes or methods, or any combinations thereof, suitable for the purposes described herein. User interface elements described herein may comprise elements from graphical user interfaces, interactive voice response, command line interfaces, and other suitable interfaces. 
     Further, the processing of the various components of the illustrated systems can be distributed across multiple machines, networks, and other computing resources. In addition, two or more components of a system can be combined into fewer components. Various components of the illustrated systems can be implemented in one or more virtual machines, rather than in dedicated computer hardware systems and/or computing devices. Likewise, the data repositories shown can represent physical and/or logical data storage, including, for example, storage area networks or other distributed storage systems. Moreover, in some embodiments the connections between the components shown represent possible paths of data flow, rather than actual connections between hardware. While some examples of possible connections are shown, any of the subset of the components shown can communicate with any other subset of components in various implementations. 
     Embodiments are also described above with reference to flow chart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products. Each block of the flow chart illustrations and/or block diagrams, and combinations of blocks in the flow chart illustrations and/or block diagrams, may be implemented by computer program instructions. Such instructions may be provided to a processor of a general purpose computer, special purpose computer, specially-equipped computer (e.g., comprising a high-performance database server, a graphics subsystem, etc.) or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor(s) of the computer or other programmable data processing apparatus, create means for implementing the acts specified in the flow chart and/or block diagram block or blocks. 
     These computer program instructions may also be stored in a non-transitory computer-readable memory that can direct a computer or other programmable data processing apparatus to operate in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the acts specified in the flow chart and/or block diagram block or blocks. The computer program instructions may also be loaded onto a computing device or other programmable data processing apparatus to cause a series of operations to be performed on the computing device or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the acts specified in the flow chart and/or block diagram block or blocks. 
     Any patents and applications and other references noted above, including any that may be listed in accompanying filing papers, are incorporated herein by reference. Aspects of the invention can be modified, if necessary, to employ the systems, functions, and concepts of the various references described above to provide yet further implementations of the invention. 
     These and other changes can be made to the invention in light of the above Detailed Description. While the above description describes certain examples of the invention, and describes the best mode contemplated, no matter how detailed the above appears in text, the invention can be practiced in many ways. Details of the system may vary considerably in its specific implementation, while still being encompassed by the invention disclosed herein. As noted above, particular terminology used when describing certain features or aspects of the invention should not be taken to imply that the terminology is being redefined herein to be restricted to any specific characteristics, features, or aspects of the invention with which that terminology is associated. In general, the terms used in the following claims should not be construed to limit the invention to the specific examples disclosed in the specification, unless the above Detailed Description section explicitly defines such terms. Accordingly, the actual scope of the invention encompasses not only the disclosed examples, but also all equivalent ways of practicing or implementing the invention under the claims. 
     To reduce the number of claims, certain aspects of the invention are presented below in certain claim forms, but the applicant contemplates the various aspects of the invention in any number of claim forms. For example, while only one aspect of the invention is recited as a means-plus-function claim under 35 U.S.C sec. 112(f) (AIA), other aspects may likewise be embodied as a means-plus-function claim, or in other forms, such as being embodied in a computer-readable medium. Any claims intended to be treated under 35 U.S.C. § 112(f) will begin with the words “means for”, but use of the term “for” in any other context is not intended to invoke treatment under 35 U.S.C. § 112(f). Accordingly, the applicant reserves the right to pursue additional claims after filing this application, in either this application or in a continuing application.