Patent Publication Number: US-2010114837-A1

Title: Remote disaster data recovery system and method

Description:
RELATED APPLICATIONS 
     This application claims priority to Provisional Application No. 60/460,226, filed Apr. 3, 2003, the entirety of which is hereby incorporated by reference. 
     This application is related to the following pending applications:
         Application Ser. No. 09/610,738, titled MODULAR BACKUP AND RETRIEVAL SYSTEM USED IN CONJUNCTION WITH A STORAGE AREA NETWORK, filed Jul. 6, 2000, attorney docket number 4982/8;   Application Ser. No. 09/609,977, titled MODULAR BACKUP AND RETRIEVAL SYSTEM WITH AN INTEGRATED STORAGE AREA FILING SYSTEM, filed Aug. 5, 2000, attorney docket number 4982/9;   Application Ser. No. 09/354,058, titled HIERARCHICAL BACKUP AND RETRIEVAL SYSTEM, filed Jul. 15, 1999, attorney docket number 4982/5;   Application Ser. No. 09/774,302, titled LOGICAL VIEW WITH GRANULAR ACCESS TO EXCHANGE DATA MANAGED BY A MODULAR DATA AND STORAGE MANAGEMENT SYSTEM, filed Jan. 30, 2001, attorney docket number 4982/11;   Application Ser. No. 09/876,289, titled APPLICATION SPECIFIC ROLLBACK IN A COMPUTER SYSTEM, filed Jun. 6, 2000, attorney docket number 4982/12;   Application Ser. No. 09/038,440, titled PIPELINED HIGH SPEED DATA TRANSFER MECHANISM, filed Mar. 11, 1998, attorney docket number 4982/6;   Application Ser. No. 10/262,556, titled SYSTEM AND METHOD FOR GENERATING AND MANAGING QUICK RECOVERY VOLUMES, filed Sep. 30, 2002 attorney docket number 4982/20; and   Application Ser. No. 60/460,234, titled SYSTEM AND METHOD FOR PERFORMING STORAGE OPERATIONS IN A STORAGE NETWORK, filed Apr. 3, 2003, attorney docket number 4982/35P;       

     each of which applications is hereby incorporated herein by reference in this application. 
    
    
     COPYRIGHT NOTICE 
     A portion of the disclosure of this patent document contains material, which is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the Patent and Trademark Office patent files or records, but otherwise reserves all copyright rights whatsoever. 
     BACKGROUND OF THE INVENTION 
     The invention disclosed herein relates generally to systems and methods for providing disaster recovery regarding computer operations. More particularly, the present invention relates to methods and systems for creating and managing remote disaster recovery copies of a volume or volumes of data and/or software. 
     Disaster recovery generally refers to a plan or strategy for duplicating computer operations, for instance, of a company, wherein copies of a volume or volumes of computer data and/or software of a primary location are established at a remote location thereby providing a redundant measure of protection in the event of a disruption of operations at the primary location. Disaster recovery thereby allows a company to resume operations in the remote location within days as opposed to, in certain instance, a permanent loss in certain aspects of the company&#39;s information infrastructure. 
     Disaster recovery systems appearing in the art provide companies with the ability to create remote backup copies of a volume or volumes of data and/or software. The information necessary to create the backup copies at the remote location is typically communicated to a remote server connected to a client computer over a communications network. Data recovery similarly entails receiving data over the communications network. Systems providing disaster recovery in this fashion, however, have numerous shortcomings with respect to creating backup copies of a volume or volumes having relatively large quantities of data and/or software. For instance, a large data transfer may increase network traffic and thereby consume a large portion of the network&#39;s capacity sufficient to slow the company&#39;s operations during the transfer. For example, creating a remote backup copy for a server computer having 100 gigabytes of data stored thereon over a company&#39;s network with multiple T1 data transfer capability will tie up the company&#39;s network for months. This is particularly problematic for companies operating around the clock that may not otherwise limit data transfer to off-peak hours and companies having networks with limited bandwidth. There is therefore a need for remote disaster recovery systems and methods having a reduced impact with regard to network traffic over a company&#39;s network. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention provides methods, systems, and software products that, among other things, enable the creation and maintenance of disaster recovery volumes having a reduced impact with regard to network traffic over a communication network. In one aspect of the present invention, this is accomplished with a disaster recovery computer system including at least one computer having programming associated therewith, the at least one computer communicatively connected to at least one local archival storage unit and at least one remote archival storage unit. The computer programming, when executed, generally provides data transfer and control capability for the creation of a disaster recovery volume of a primary volume at the local storage unit on at least one storage medium, which storage medium constitutes the disaster recovery volume. The programming also associates the storage medium constituting the disaster recovery volume with the primary volume, which allows the storage medium to be relocated to a remote location without compromising the association between the primary volume and the disaster recovery volume. In one embodiment the programming associates the storage medium or media constituting the disaster recovery volume with the primary volume by including therein indicia for identifying the medium as at least a portion of the disaster recovery volume of the primary volume. The indicia may be a tag included in each medium constituting the disaster recovery volume identifying the source of data therein and information regarding the date and time the disaster recovery volume was created. 
     In one embodiment, the at least one computer is a plurality of computers including at least one client computer and at least one server computer. The client computer having programming associated therewith that provides data transfer and control capability thereto capable of packaging and communicating primary volume data, e.g., the primary data set, to the local storage unit. The programming may be at least one intelligent data agent program module, which provides application specific data packaging capability to the client computer. The server computer may include at least one of a media agent program module and a storage manager program module, the server computer adopted therewith to receive packaged data from the client computer and control the transfer of the packaged data to the local archival storage unit. The server computer may also include at least one of a media agent program module and a storage manager program module, the server computer adopted therewith to receive packaged data and control the transfer of the packaged data to the remote archival storage unit. 
     The client computer may also include at least one quick recovery agent program module that provides therewith snapshot image packaging capability. In this instance, the quick recovery agent module packages a snapshot image of the primary volume for the creation of the disaster recovery volume of the primary volume at the local archival storage unit. The disaster recovery volume may be created in a variety of formats. In one embodiment, the disaster recovery volume is a snapshot image of the primary volume. 
     In one embodiment, the client computer includes at least one intelligent data agent program module that provides application specific data packaging capability, the client computer therewith capable of identifying and packaging incremental changes to the primary volume. The server computer may also include at least one of a media agent program module and a storage manager program module, the server computer adopted therewith to receive packaged data representing the incremental changes to the primary volume and control the transfer of the packaged data to the remote archival storage unit. 
     The server computer may also include at least one media agent program module, the server computer adopted therewith to create a disaster recovery volume of a primary volume from at least one copy selected from the group consisting of: a backup volume of the primary volume, a quick recovery volume of the primary volume, and a snapshot image of the primary volume. The server computer may also include at least one media agent program module, the server computer adopted therewith to create a disaster recovery volume of a primary volume in connection with a quick recovery volume. In this instance, the disaster recovery volume is created from at least one snapshot image of the primary volume. 
     The server computer may also include at least one media agent program module, the server computer adapted therewith to effect incremental changes to a disaster recovery volume relocated to the remote storage unit. The incremental changes to the disaster recovery volume represent incremental changes to the primary volume. The incremental changes to the disaster recovery volume, in one embodiment, are made in connection with at least one snapshot image of the primary volume taken after the creation of the disaster recovery volume. 
     In another aspect of the present invention, a computer readable medium is providing which stores therein program code which when executed on a computer, causes the computer to perform a method for creating a disaster recovery volume of a primary volume associated with a first computer. The method, in one embodiment, includes the steps of packaging a primary data set associated with the primary volume, communicating the packaged primary data set associated with the primary volume to a local archival storage unit which includes therein at least one storage medium, copying the packaged primary data set to the at least one storage medium, the at least one storage medium constituting the disaster recovery volume; and associating the at least one storage medium constituting the disaster recovery volume with the primary volume thereby allowing the storage medium constituting the disaster recovery volume to be relocated to a remote archival storage unit at a remote location without compromising the association between the primary volume and the disaster recovery volume. The step of associating the primary volume and the disaster recovery volume may entail including in the medium indicia for identifying the medium as at least a portion of the disaster recovery volume of the primary volume. The indicia may be a tag included in each medium constituting the disaster recovery volume that identifies the source of data therein and information regarding a date and time the disaster recovery volume was created. 
     The method of creating a disaster recovery volume may also include the step of synchronizing at least one of an application and an operating system associated with the first computer so that essentially all data of the primary data set is copied to the local archival storage unit and so that the primary data set is not modified during the creation of the disaster recovery volume at the local archival storage unit. The synchronizing step may, in certain instances, entail suspending input and/or output to a disk containing at least a portion of the primary data set, and resuming input and/or output to the disk containing at least a portion of the primary data set after the creation of the disaster recovery volume. In one embodiment, the disaster recovery volume is a snapshot image of the primary volume. 
     The method of creating a disaster recovery volume may also include the steps of identifying incremental changes to the primary volume, packaging data representing incremental changes to the primary volume, and communicating the packaged data over a communications network to the remote storage unit at a remote location. The step of packaging data representing incremental changes to the primary volume may include compressing the data representing incremental changes to the primary volume. The incremental changes to the primary volume may then be incorporated into the disaster recovery volume relocated to the remote location. The incremental changes to the primary volume may be identified in connection with at least one snapshot image of the primary volume. The disaster recovery volume of a primary volume may be made from at least one copy selected from the group consisting of a backup volume of the primary volume, a quick recovery volume of the primary volume, and a snapshot image of the primary volume. 
     In another aspect of the invention, a method for creating a disaster recovery volume of a primary volume is provide that includes the steps of creating a backup copy of at least a portion of a primary volume on at least one storage medium at a first location, physically transferring the at least one storage medium to a second location remote from the first location, and updating the backup copy at the second location over a communications network to reflect incremental changes to the primary volume subsequent to the creation of the primary backup copy. In one embodiment, the step of creating a backup copy includes the step of associating the storage medium with the primary volume thereby allowing the storage medium to be relocated to the second remote location. In another embodiment, the step of creating a backup copy includes the step of synchronizing at least one of an application and an operating system associated with the primary volume to allow essentially all data of the primary volume to be copied to the storage medium and to prevent the primary volume from being modified. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention is illustrated in the figures of the accompanying drawings which are meant to be exemplary and not limiting, in which like references are intended to refer to like or corresponding parts, and in which: 
         FIG. 1  is a block diagram depicting software components and communication paths of program code stored on a computer readable medium providing remote disaster recovery functionality according to at least one embodiment of the invention; 
         FIG. 2  is a disaster recovery computer system according to an embodiment of the invention; and 
         FIG. 3  is a flow diagram of a method of creating a disaster recovery volume according to an embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIG. 1 , software components that may be stored on a computer readable medium enabling the creation and management of disaster recovery volumes of a primary data set associated with a client computer, according to an embodiment of this invention, include at least one agent module  102 , such as an intelligent data agent  104 , a quick recovery agent  108 , a media agent  106 , etc., and at least one storage manager module  110 . A primary data set generally denotes data, application data, software, executable code, and/or other data and computer programming associated with a client computer that may be used as the source to create the disaster recovery volume  124 . A volume generally refers to a physical or logical storage unit, or a portion thereof, which may be stored on one or more data storage devices. A primary volume generally refers to a volume or a portion thereof having the primary data set stored thereon. 
     An agent module  102  is used herein to generally refer to a program module or application that provides data transfer and control functionality to client computers. A client as used herein refers to a computer with data and/or application programming associated therewith stored on one or more storage media that may be backed up and/or restored in accordance with a disaster recovery plan or restoration. A client therefore includes, but is not limited to, a personal computer, workstation, mainframe computer, a host computer, etc. An intelligent data agent  104  refers to an agent module particular to a specific application, such as Windows 2000 File System, Microsoft Exchange 2000 Database, etc., that provide control and data transfer functionality for data protection and recovery operations of the data and/or programming for the specific applications. A plurality of agents modules  102 , such as intelligent data agents  104  and/or quick recovery agents  108 , may therefore be provided and/or reside on each client computer, for example, where the client computer includes a plurality of applications and a file system or systems for which a disaster recovery volume may be created and maintained. 
     A media agent  106  as used herein generally refers to a software module that provides data transfer control for archival storage units  112 , such as tape library, a redundant array of independent disk (“RAID”) system, etc., and facilitates local and remote data transfer to and from local and remote archival storage units  112 ,  126 , or between the clients and the local and/or remote archival storage units  126 . The media agent  106  may interface with one or more agents modules  102 , such as the intelligent data agent or agents  104 , quick recovery agent  108 , or another media agent  106 , to control the data being copied from a client computer to a local or remote archival storage unit  112 ,  126  and/or to a remote archival storage unit  126  from a local archival storage unit  112 . The media agent  106 , in on embodiment, controls data transfer to and from a primary volume  114  containing the primary data set to create and maintain at least one of a backup volume  122 , a quick recovery volume  118 , and a disaster recovery volume  124 . Moreover, the media agent  106  may control data transfer to create and maintain a disaster recovery volume from either of the backup volume  122  or quick recovery volume  118 . 
     A storage manager  110  as used herein generally refers to a software module or application that acts as an interface between the plurality of agents, such as the intelligent agents  104 , media agents  106 , quick recovery agents  108 , etc., clients, storage units, etc., and in one embodiment, coordinates and controls data flow between them for data protection and recovery operations. The storage manager may also provide scheduling functionality for the creation of either the backup volumes  114 , quick recovery volumes  118 , and the disaster recovery volumes  124 . The primary volumes  114 , quick recovery volume  118 , backup volumes  122 , and disaster recovery volume  124 , may be stored to a variety of storage devices and media, such as tape drives, hard drives, optical drives, etc. In one embodiment, the disaster recovery volume  124  is stored on removable media, such as tape or optical media. The storage devices associated with client computers may be local to the client, such as local drives, or remote to the client, such as remote drives on a storage area network (“SAN”), local area network (“LAN”), or wide area network (“WAN”), etc. The backup volumes  122 , the quick recovery volumes  118 , and, disaster recovery volume  124  may be snapshot images of the primary volume  114 , exact replicas of the primary volume  114 , or a compressed version thereof. 
     A quick recovery agent  108  generally refers to a software module that provides the ability to create snapshot images and quick recovery volumes  118 . The quick recovery agent  108  evokes a snapshot mechanism or interfaces with a snapshot manager that provide for the creation of a snapshot image of the primary volume  114 , which may be used to create a quick recovery volume  118 , a backup volume  122 , or a disaster recovery volume of the primary data set. In one embodiment, the quick recovery agent  108  interfaces with snapshot image programming, such as XP/.NET, TimeFinder, etc., that creates snapshot images or shadowed copies of the primary data set. In one embodiment, the quick recovery agent  108  interfaces with a snapshot manager agent module, which may be an intelligent agent, that generally controls data transfer from the primary volume  114  for the creation of a snapshot image, and a snapshot requestor and writer agent modules, which may also be an intelligent agents, which package the primary data set for the creation of the snapshot image by the snapshot image programming. Aspects of the quick recovery volumes and agents are discussed in greater detail in U.S. application Ser. No. 10/262,556, entitled SYSTEM AND METHOD FOR GENERATING AND MANAGING QUICK RECOVERY VOLUMES, which is hereby incorporated herein by reference. 
     Referring to  FIG. 2  a disaster recovery computer system, according to one embodiment of the invention, includes at least one server computer  304 ,  308  communicatively connected to at least one client computer  302 , such as a personal computer, a workstation, a server computer, a host computer, a mainframe computer, etc., and at least one archival storage unit over a communications network  306 . In one embodiment, the system includes at least one local archival storage unit  112  and at least one remote archival storage unit  126 . The communications network  306  is any suitable communications link, such as a LAN, WAN, the Internet, or any combinations thereof. In one embodiment, the communications network  306  includes at least one LAN that interconnects client computers  302 , server computers  304  and local archival storage units  112  at a primary location, and a WAN that connects the computers at the primary location with the equipment at a remote location, e.g., remote server  308  and/or the remote archival storage unit  126 . A remote location is herein used to denote a geographic location other than the location or locations of the primary volume  114 . The distance between the remote and primary location may vary depending on the desired level of redundancy. For instance, disaster recovery enabled to provide redundancy in the event of a local power failure may be achieved by separating the primary and remote sites such that the locations are not in the same building. A greater level of redundancy may be achieved by separating the location such that they do not share a common power supply source, such as in a different town, city, state, country, etc. For example, a local site may be located in New York City and a remote site in Dallas Tex. 
     In one embodiment of the present invention, the client computers  302  contain programming, such as intelligent data agents  104 , media agents  106 , quick recovery agents  108 , and/or a storage manager  110 , which provides the functionality for creating and maintaining local and/or remote copies, and/or snapshot images of a primary data set. The copies may be at least one of backup volumes  122 , quick recovery volumes  118 , and a disaster recovery volume or volumes  124 . The backup volumes may further be primary copies, secondary copies, etc. The copies may be stored or copied either locally at the client computer, such as on a local hard drive, tape drive, optical drive, etc., or remote from the client on at least one local archival storage unit  112 , such as a tape library, a stand alone drive, a RAID cabinet, etc. In one embodiment, at least one of the copies, such as the disaster recovery volumes  124 , is stored and maintained at a remote site. 
     The client computer  302 , according to one embodiment, includes at least one intelligent data agent  104 , which provides the data transfer and control functionality for the client computer  302 . The intelligent data agent  104  provides the data transfer and control functionality by identifying and packaging the application specific data of the primary volume  114  to be backed up. Packaging generally denotes parsing data and logically addressing the data that is to be used in order to facilitate the creation of the disaster recovery volume  124 . For example, where a snapshot of the Microsoft Exchange application is to be created, the Exchange specific intelligent agent will parse the relevant data from the primary volume  114 , e.g., the disk or disks containing the application data, and logically address the parsed data to facilitate rebuilding the parsed data for the disaster recovery volume  124 . In one embodiment, the intelligent data agent  104 , which can be aided by the storage manager  110 , packages the primary data set into a backup format or other format and copies the data to a backup copy or copies. For example, in some embodiments an intelligent data agent  104  packages a the data according to Galaxy&#39;s backup format or another backup format or secondary storage format as further described in U.S. Pat. Nos. 5,559,991, 5,642,496, and 6,418,478 each of which is hereby incorporated herein by reference in their entirety. In some embodiments, the intelligent data agent  104  packages additional information with the primary data such as information regarding how applications recognize the data, where data is physically located on the backup copy, where snapshot data is logically located on the backup copy, application-specific preferences associated with the data, and other information. The additional information can be included, for example, in header information of the data, in the payload of the data, or in combinations thereof. In some embodiments, the intelligent data agent  104  does not package the data into a backup format, and instead copies the data in its original format, for example, in the case of creating a quick recovery volume or a disaster recovery volume. 
     In one embodiment, the client computer includes at least one quick recovery agent  108 , which creates or interfaces with a snapshot image program to create a snapshot image of the primary volume for use in the creation of the disaster recovery volume  124 . The primary data set may thus be packaged by the quick recovery agent  108  or by snapshot requestor and writer agents, which interface with the quick recovery agent  108 . 
     As noted above, the client computer  302  may also be a server computer  304 , and may therefore also include programming, such as a media agent  106  and/or a storage manager  110 , which controls data transfer to and from the client computers  302  and the archival storage units  112 ,  126 . In one embodiment, at least one server  304  at the primary location and at least one server at the remote site  308  include programming, such as at least one media agent  106  and a storage manager  110  that control data transfer between a client computer  302  at the primary site and, a local and/or remote archival storage unit  126 . 
     Disaster recovery having a reduced impact on network traffic, according to the present invention, generally entails initially creating a disaster recovery volume  124  locally at a primary location and later transferring the disaster recovery volume  124  to a remote location to provide the requisite redundancy in accordance with the disaster recovery plan. For example, a disaster recovery volume of a server A in New York City may initially be created in New York City and later removed from server A or a archival storage unit associated therewith and installed in an archival storage unit B in a remote site in Dallas. Redundancy with respect to changes in the primary volume  114 , e.g., the primary data set, subsequent to the creation of the disaster recovery volume  124  may further be provided by incrementally changing or effecting changes to the disaster recovery volume  124  at the remote location to reflect the changes to the primary volume  114  at the primary location. This aspect of the invention effectively alleviates network traffic that would otherwise be required to create a disaster recovery volume  124  at the remote site over the communication network. It is understood that this aspect of the present invention may be accomplished in a variety of ways. 
     Referring to  FIG. 3 , a method of creating a disaster recovery volume, according to one embodiment, begins by synchronizing the applications and/or operating system associated with a client computer  302  to ensure that essentially all data of the primary volume  114  to be backed up in accordance with a disaster recovery plan is copied to the local archival storage unit  112  where the disaster recovery volume  124  will be stored at least initially during the creation of the disaster recovery volume  124  and to ensure, among other things, that the primary data set is not modified during the creation of the disaster recovery volume  124 , step  350 . This may be accomplished, for instance, by suspending input and/or output to the disk containing the primary data set, which will ensure that the file system and metadata remain unchanged during the copy operation. Alternatively or in addition, the disk or disks comprising the primary volume  114  may be dismounted during the copy operation and remounted when the copy is complete. In another alternative embodiment, input and/or output to the disk containing the primary data set is not suspended and/or unmounted during the copy operation. 
     The primary volume  114 , e.g., the primary data set, may then be packaged, e.g., by the intelligent data agent  104  and/or the quick recovery agent  108 , step  352 , and communicated, step  354 , to the local archival storage unit  112  for the creation of the disaster recovery volume  124 . As noted above, the disaster recovery volume  124  may be a snapshot image of the primary volume  114 , an exact replica of the primary volume  114 , or a compressed version thereof. Thus, the intelligent data agent  104  and/or the quick recovery agent  108  may additionally compress the primary data set in the packaging process. The packaged data may be communicated to either a media agent  106  and/or a storage manager  110 , at a local and/or a server computer  302 ,  308 , which generally control the data transfer between the client devices  302  and the archival storage units  112 ,  126 . 
     In one embodiment, at least one storage medium that will constitute the disaster recovery volume  124  at the local archival storage unit  112  is associated with the primary volume  114 , step  356 . Associating the media generally denotes including therein indicia or other means for identifying the media as being or belonging to a set of media that constitute the disaster recovery volume  124  of a primary data set such that the disaster recover volume  124  may be removed from the primary location and relocated to a remote site without compromising the association between the primary volume  114  and the disaster recovery volume  124 , which may result in corrupting the data thereon. This may be accomplished, for instance, by including appropriate identifying information in the header of the storage media or including a tag in each medium, which identifies the source of the data for the disaster recover volume  124 , such as the particular client computer  302 , the primary volume  114 , etc. The header or tag may also provide information with regard to when the disaster recovery volume was created, such as the date and time of creation. The association provides, for instance, means for ensuring that, after relocating the disaster recovery volume  124  to a remote site, subsequent incremental updates to the primary volume A, for example, may be incorporated into the disaster recovery volume of the primary volume A and not in disaster recovery volume for any other primary volume, which may result in corrupting the data therein. The association further provides means for ensuring that multiple incremental updates in the primary volume are properly applied to the disaster recovery volume in proper order further preventing data corruption. 
     The packaged data may then be copied to the disaster recovery storage medium or media, step  360 . It is also understood that the copy procedure may be accomplished in a variety of ways and also using a variety of methods. For instance, the copy operation may be a disk-to-disk data-block-level replication of the primary data set to provide an exact replica of the primary volume  114 , the creation of an image or the primary volume  114 , or may incorporate data compression to produce a compressed versions thereof. Additionally, the disaster recovery volume  124  may be created from previous backup volumes  122 , such as primary and secondary copies, a quick recovery volume  118 , or one or more snapshot images of the primary volume  114 . Copying from or in connection with a quick recovery volume  118  and/or snapshot images of the primary volume  114  entails creating the copy of the primary data set from a snapshot image or images of the primary data set as opposed to the actual primary volume  114  thereby minimizing the suspension of the input or output to primary volume  114 . Once the disaster recovery volume  124  is created, input or output to the primary volume disk or disks may then resume. 
     The disaster recovery volume  124  may then physically be removed from the local archival storage unit  112  at its initial storage location at the primary site, such as by removing the media from a tape or optical jukebox, and physically transferred or relocating the disaster recovery volume  124  to the remote site, step  362 . The transfer process entails transporting the media constituting the disaster recovery volume  124  to the remote site, which may be located in a different city, state, country, etc., where the disaster recovery volume  124  may be placed into the remote archival storage unit  126 , e.g., the tape or optical jukebox. The disaster recovery volume  124  may then be made available as a remote disaster recovery volume  124  for data protection and/or recovery of the primary data volume  114  based on the media association with the primary volume, step  364 . 
     Once the disaster recovery volume  124  is made available, incremental changes to the primary data set or to the primary volume may be tracked and communicated to the remote site over the communications network  306  so that the incremental changes may be incorporated into the disaster recovery volume  124  at the remote location, step  374 . The incremental changes may be made periodically, such as daily, weekly, etc. It is understood that the incremental changes may be incorporated into the disaster recovery volume  124  in a variety of ways. In one embodiment, incrementally changes to the primary volume are incorporated into the disaster recovery volume  124  by first synchronizing the applications and/or operating system of a client computer associated with the primary volume  114 , step  368 . Incremental changes to blocks of data of the primary volume  112  after the creation of the disaster recovery volume  124  or any previous incremental update to the disaster recovery volume  124  of the primary volume  114  may then be packaged, such as by the intelligent data agent  104  or quick recovery agent  108 , step  370 , and communicated over a communications network  306  to the remote site, e.g., the remote archival storage unit  126 , step  372 , where the packaged data will be incorporated into the particular disaster recovery volume  124  for the primary volume  124 , step  374 . The packaged data may be packaged in a storage operation format, a backup format, a compressed format, or the original format. 
     In some embodiments, the intelligent data agent  104  and/or the quick recovery agent  108  packages additional information with the changed blocks such as information regarding how applications recognize the changed block data, where changed block data is physically located on the primary volume  114 , where changed block data is logically located on the primary volume  114 , application-specific preferences associated with the changed block data, and other information. The additional information can be included in header information of the changed block data being copied to the disaster recovery volume  124 , in the payload of the changed block data being copied to the disaster recovery volume  124 , or in combinations thereof. The incremental changes may also be made in conjunction with snapshot images of the primary volume taken after the creation of the disaster recovery volume further reducing the suspension of access to the primary volume  114 . The data recovery volume  124  of the primary volume  114  is therefore, in accordance with the present invention, available as a disaster recovery volume  124 , which is available for resumed operations in the event of a disruption of operations at the primary location and/or for data recovery, and which was created with limited or reduced impact with regard to network traffic on the companies network. 
     Some of the embodiments of the present invention leverage existing features of the CommVault Galaxy backup system. It will be recognized by those skilled in the art, however, that the embodiments of the present invention may be applied independently of the Galaxy system. While the invention has been described and illustrated in connection with preferred embodiments, many variations and modifications as will be evident to those skilled in this art may be made without departing from the spirit and scope of the invention, and the invention is thus not to be limited to the precise details of methodology or construction set forth above as such variations and modification are intended to be included within the scope of the invention.