Abstract:
Embodiments of the present invention disclose a method, computer program product, and system for snapshot management in a storage infrastructure. A computer accesses a first snapshot captured in a first layer of the storage infrastructure. The computer accesses a second snapshot captured in a second layer of the storage infrastructure. The computer produces a determination that the first snapshot in the first layer of the storage infrastructure is one or more of: inconsistent with the second snapshot in the second layer of the storage infrastructure and a duplicate of the second snapshot in the second layer of the storage infrastructure. The computer removes the first snapshot in the first layer of storage infrastructure responsive to the determination.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates generally to the field of data management, and more particularly to snapshot management in hierarchical storage infrastructure. 
       BACKGROUND OF THE INVENTION 
       [0002]    Information Technology (IT) infrastructure environments can include a hierarchical storage infrastructure which can be used to create and store snapshots in different layers of hierarchical storage infrastructure. IT infrastructure environments utilize servers and server virtualizers in conjunction with storage area networks (SAN) and storage virtualizers to provide the capability to create and manage snapshots. A SAN provides access to consolidated, block level data storage and can be used to make storage devices (i.e., disk arrays) accessible to servers so that the storage devices can appear to be locally attached to the operating system. A snapshot is a usable copy of a defined collection of data that contains an image of how the data appeared at a point in time. In some examples, snapshots may also be referred to as point in time copies. Infrastructure environments are becoming increasingly complex, which leads to an increasing importance of snapshots. 
       SUMMARY 
       [0003]    Embodiments of the present invention disclose a method, computer program product, and system for snapshot management in a storage infrastructure. A computer accesses a first snapshot captured in a first layer of the storage infrastructure. The computer accesses a second snapshot captured in a second layer of the storage infrastructure. The computer produces a determination that the first snapshot in the first layer of the storage infrastructure is one or more of: inconsistent with the second snapshot in the second layer of the storage infrastructure and a duplicate of the second snapshot in the second layer of the storage infrastructure. The computer removes the first snapshot in the first layer of storage infrastructure responsive to the determination. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0004]      FIG. 1  is a functional block diagram of a data processing environment, in accordance with an embodiment of the present invention. 
           [0005]      FIG. 2  is a flowchart depicting operational steps of a program for migrating and consolidating snapshots in an IT infrastructure environment, in accordance with an embodiment of the present invention. 
           [0006]      FIG. 3  depicts a block diagram of components of the computers of  FIG. 1 , in accordance with an embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0007]    Embodiments of the present invention recognize that multiple copies of the same data in different layers of an IT infrastructure environment wastes space. In an example, snapshots of data in IT infrastructure environments can cause a large amount of repetitive data, which will lead to wasted space. Users and administrators of the IT infrastructure environment may not be aware of existing snapshots throughout the layers of the IT infrastructure environment. In an example, an administrator may take a snapshot of a virtual machine but is not aware a user has previously taken a snapshot of certain components inside the virtual machine. Embodiments of the present invention also recognize manually collecting and joining all existing information regarding snapshots in all layers of an IT infrastructure environment can become a time-consuming process. 
         [0008]    As will be appreciated by one skilled in the art, aspects of the present invention may be embodied as a system, method, or computer program product. Accordingly, aspects of the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment (including firmware, resident software, micro-code, etc.), or an embodiment combining software and hardware aspects that may all generally be referred to herein as a “circuit,” “module,” or “system.” Furthermore, aspects of the present invention may take the form of a computer program product embodied in one or more computer readable medium(s) having computer readable program code/instructions embodied thereon. 
         [0009]    Any combination of computer readable media may be utilized. Computer readable media may be a computer readable signal medium or a computer readable storage medium. A computer readable storage medium may be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples (a non-exhaustive list) of a computer readable storage medium would include the following: an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In the context of this document, a computer readable storage medium may be any tangible medium that can contain or store a program for use by or in connection with an instruction execution system, apparatus, or device. 
         [0010]    A computer readable signal medium may include a propagated data signal with computer readable program code embodied therein, for example, in baseband or as part of a carrier wave. Such a propagated signal may take any of a variety of forms, including, but not limited to, electro-magnetic, optical, or any suitable combination thereof. A computer readable signal medium may be any computer readable medium that is not a computer readable storage medium and that can communicate, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device. 
         [0011]    Program code embodied on a computer readable medium may be transmitted using any appropriate medium, including, but not limited to, wireless, wireline, optical fiber cable, RF, etc., or any suitable combination of the foregoing. 
         [0012]    Computer program code for carrying out operations for aspects of the present invention may be written in any combination of one or more programming languages, including an object-oriented programming language, such as Java®, Smalltalk, C++ or the like and conventional procedural programming languages, such as the “C” programming language or similar programming languages. The program code may execute entirely on a user&#39;s computer, partly on the user&#39;s computer, as a stand-alone software package, partly on the user&#39;s computer and partly on a remote computer, or entirely on the remote computer or server. In the latter scenario, the remote computer may be connected to the user&#39;s computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet Service Provider). 
         [0013]    Aspects of the present invention are described below with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks. 
         [0014]    These computer program instructions may also be stored in a computer readable medium that can direct a computer, other programmable data processing apparatus, or other devices to function in a particular manner, such that the instructions stored in the computer readable medium produce an article of manufacture including instructions which implement the function/act specified in the flowchart and/or block diagram block or blocks. 
         [0015]    The computer program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other devices to cause a series of operational steps to be performed on the computer, other programmable apparatus, or other devices to produce a computer-implemented process such that the instructions which execute on the computer or other programmable apparatus provide processes for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks. 
         [0016]    The present invention will now be described in detail with reference to the Figures.  FIG. 1  is a functional block diagram illustrating data processing environment  100 , in accordance with one embodiment of the present invention. 
         [0017]    Data processing environment  100  includes IT infrastructure environment  110 , I/O system  140 , and hierarchical snapshot manager  150 . In one exemplary embodiment, IT infrastructure environment  110 , I/O system  140 , and hierarchical snapshot manager  150  can be desktop computers, specialized computer servers, or any other computer systems known in the art. In certain embodiments, IT infrastructure environment  110 , I/O system  140 , and hierarchical snapshot manager  150  represent computer systems utilizing clustered computers and components (e.g., database server computers, application server computers, etc.) acting as a single pool of seamless resources when accessed by elements of data processing environment  100 . In general, IT infrastructure environment  110 , I/O system  140 , and hierarchical snapshot manager  150  are representative of any electronic device or combination of electronic devices capable of executing machine-readable program instructions, as described in greater detail with regard to  FIG. 3 . In one embodiment, IT infrastructure environment  110  includes storage devices organized in a hierarchical structure corresponding to various layers of the IT infrastructure environment. In an embodiment, the elements of data processing environment  100  can communicate through network connections, such as a local area network (LAN), a telecommunications network, a wide area network (WAN), such as the Internet, or a combination of the three, and include wired, wireless, or fiber optic connections. In another example, I/O system  140  and hierarchical snapshot manager  150  can be located within IT infrastructure environment  110 . 
         [0018]    IT infrastructure environment  110  is an exemplary depiction of an environment of a hierarchical storage infrastructure, which includes layer  1  snapshot manager  120  and layer  2  snapshot manager  130 . In one embodiment, layer  1  snapshot manager  120  and layer  2  snapshot manager  130  control the creation, deletion, and storage of snapshots in IT infrastructure environment  110 . Each layer of IT infrastructure environment  110  capable of taking snapshots has a snapshot manager (i.e., layer  1  snapshot manager  120  and layer  2  snapshot manager  130 ). Layer  1  snapshot manager  120  and layer  2  snapshot manager  130  are instances of snapshot management systems each corresponding to a certain layer of IT infrastructure environment  110 . In one embodiment, layer  1  snapshot manager  120  and layer  2  snapshot manager  130  can be representations of the same type of snapshot management system (including the same components) residing on different layers of IT infrastructure environment  110 , wherein each snapshot manager includes data corresponding to the layer of IT infrastructure environment  110  that the snapshot manager resides on. In another example, IT infrastructure environment  110  can include more than two layers capable of taking snapshots. In such an example, a snapshot manager can exist on each layer of IT infrastructure environment  110  capable of taking snapshots. In one embodiment, layer  1  snapshot manager  120  includes snapshot engine  122  and snapshot data manager  124 , and layer  2  snapshot manager  130  includes snapshot engine  132  and snapshot data manager  134 . Snapshot engines  122  and  132  control the snapshot creation and deletion aspects of layer  1  snapshot managers  120  and  130  respectively. Snapshot data managers  124  and  134  maintain snapshot metadata and snapshot data corresponding to, at least in part, snapshotted entities in IT infrastructure environment  110 , a snapshot time, and a storage location for a snapshot. In one embodiment, snapshot engines  122  and  132  communicate with respective snapshot data managers  124  and  134  to share information about snapshots (i.e., creation and deletion of snapshots), which snapshot data manager can then store. 
         [0019]    In one embodiment, I/O system  140  keeps track of snapshot updates of storage entities in the layers of IT infrastructure environment  110  and parent storage entities that correspond to other storage entities in the IT infrastructure environment. I/O system  140  can communicate with snapshot data managers  124  and  134  to share information corresponding to snapshots of entities in IT infrastructure environment  110 . 
         [0020]    Hierarchical snapshot manager  150  includes hierarchical snapshot engine  152 , hierarchical asset history  154 , hierarchical snapshot data manager  156 , and hierarchical snapshot management program  200 . In one embodiment, hierarchical snapshot manager  150  can access snapshots and snapshot information throughout all layers of IT infrastructure environment  110 . Hierarchical snapshot engine  152  is responsible for controlling the migration of snapshots throughout the layers of IT infrastructure environment  110 . Hierarchical snapshot engine  152  can communicate with snapshot engines  122  and  132  to perform snapshot configuration changes, such as deleting, creating, or restoring snapshots. In one embodiment, hierarchical asset history  154  is a database for collecting and storing information corresponding to all snapshots from all snapshot managers (i.e., layer  1  snapshot manager  120  and layer  2  snapshot manager  130 ) in IT infrastructure environment  110 . The snapshot information in hierarchical asset history  154  includes, at least in part, a layer in IT infrastructure environment  110  corresponding to the snapshot, snapshot size, snapshot time, and snapshot storage information. Hierarchical asset history  154  can be implemented with any type of database storage capable of storing data which may be accessed and utilized by elements of IT infrastructure environment  110  and I/O system  140 , such as a database server, a hard disk drive, or flash memory. In an embodiment, layer  1  snapshot manager  120  or layer  2  snapshot manager  130  can notify hierarchical asset history  154  of changes to snapshot information through communication with I/O system  140 . Hierarchical snapshot engine  152  can communicate with hierarchical asset history  154  in order to reflect actions taken by the hierarchical snapshot engine. In one embodiment, hierarchical snapshot engine  152  can communicate with hierarchical asset history  154  and hierarchical snapshot data manager  156  to utilize snapshot information to identify redundant, overlapping, and inconsistent snapshots hierarchical snapshot management program  200  can remove or migrate within IT infrastructure environment  110 . Hierarchical snapshot data manager  156  manages copies of snapshot metadata for utilization in hierarchical snapshot manager  150 . In one embodiment, hierarchical snapshot data manger  156  analyzes and correlates snapshot information from hierarchical asset history  154 . Hierarchical snapshot data manager  156  can communicate with hierarchical asset history  154  to analyze snapshot information to determine duplicate snapshots and inconsistent snapshots stored in hierarchical asset history. Hierarchical snapshot manager  150  utilizes hierarchical snapshot management program  200  to migrate and consolidate snapshots stored in IT infrastructure environment  110 . Hierarchical snapshot management program  200  is discussed in greater detail with regard to  FIG. 2 . 
         [0021]      FIG. 2  is a flowchart depicting operational steps of hierarchical snapshot management program  200 , in accordance with an exemplary embodiment of the present invention. 
         [0022]    In step  202 , hierarchical snapshot management program  200  identifies snapshots stored in an IT infrastructure environment. In one embodiment, hierarchical snapshot management program  200  accesses snapshot managers (i.e., layer  1  snapshot manager  120  and layer  2  snapshot manager  130 ) on layers of IT infrastructure environment  110  in order to identify snapshots. In an example, hierarchical snapshot management program  200  accesses layer  1  snapshot manager  120  to identify the snapshots existing on layer  1  snapshot manager  120  of IT infrastructure environment  110 , and the snapshot information corresponding to each snapshot. The snapshot information can include at least in part the snapshot size, the creation time of the snapshot, and the storage method and location of the snapshot. In this example, hierarchical snapshot management program  200  continues to access other layers of IT infrastructure environment  110  and identifies existing snapshots and corresponding snapshot information. In one embodiment, hierarchical snapshot management program  200  determines relationships of snapshots in every layer of IT infrastructure environment  110 , even layers that do not include a snapshot manager. 
         [0023]    In step  204 , hierarchical snapshot management program  200  determines possible relationships between identified snapshots of the IT infrastructure environment. In one embodiment, hierarchical snapshot management program  200  utilizes the snapshots identified in step  202  and determines the possible snapshot relationships to IT infrastructure environment  110 . In an example, hierarchical snapshot management program  200  accesses snapshot data managers  124  and  134  and utilizes snapshot metadata to determine relationships. The relationships hierarchical snapshot management program  200  determines include entities of IT infrastructure environment  110  included in each snapshot, wherein the entities of the IT infrastructure environment can include storage elements, elements capable of creating snapshots, or other elements of the IT infrastructure environment. Data collection by hierarchical snapshot management program  200  can include all layers and elements of IT infrastructure environment  110  having snapshots. In an example, hierarchical snapshot management program  200  identifies and correlates relationship data for snapshots corresponding to snapshots of layer  1  snapshot manager  120  with a corresponding storage structure (i.e., virtual storage locations, separate physical disc storage) within IT infrastructure environment  110 . In this example, hierarchical snapshot management program  200  repeats the identifying and correlating process for each layer of IT infrastructure environment  110 . In one embodiment, relationship information that hierarchical snapshot management program  200  uses to correlate the storage structure includes, but is not limited to, snapshotted entities, layers that snapshotted entities relate to, parent entities of snapshotted entities, snapshots including a certain entity, and snapshot timestamps. A parent entity of a snapshotted entity can be an entity within IT infrastructure environment  110  containing or controlling the snapshotted entity as a subsidiary. In various embodiments, parent entities have one or more corresponding child entities. In examples with regard to IT infrastructure environment  110 , a snapshotted entity can have a relationship with a parent entity, wherein the parent entity contains the storage location of the snapshotted entity or can control the actions of the snapshotted entity. In some examples, determined relationships can relate to, layers of IT infrastructure environment  110  that store identified snapshots, entities of the IT infrastructure environment included in snapshots, relationships of snapshots to parent entities, snapshot timestamps, and snapshot storage locations. The collection of determined relationships of existing snapshots results in a hierarchical organization of the entities of IT infrastructure environment  110 . 
         [0024]    In step  206 , hierarchical snapshot management program  200  identifies redundant snapshots, overlapping snapshots, and inconsistent snapshots. In one embodiment, hierarchical snapshot management program  200  utilizes snapshot metadata, snapshot information, and relationship data to identify redundant, overlapping, or inconsistent snapshots identified in step  202 . Hierarchical snapshot management program  200  considers snapshots to be redundant when a snapshot includes a parent entity that has a relationship with another snapshot. In an example, a redundant snapshot can be a snapshot including a storage device, wherein the storage device contains another snapshot. Hierarchical snapshot management program  200  considers snapshots to be overlapping when separate snapshots exist of an entity and its parent entity. In an example, if a snapshot of a portion of a storage device and a snapshot of the entire storage device exist, then the snapshots are overlapping. Hierarchical snapshot management program  200  considers snapshots to be inconsistent when a snapshotted entity has multiple parent entities, but for one or more of the parent entities of the snapshotted entity, a snapshot does not exist, or the snapshots of the parent entities are not taken simultaneously (i.e., do not have the same timestamps). 
         [0025]    In step  208 , hierarchical snapshot management program  200  consolidates the identified redundant, overlapping, and inconsistent snapshots. In one embodiment, hierarchical snapshot management program  200  consolidates snapshots by migrating snapshots and snapshot data and removing unnecessary snapshot data. Snapshots and snapshot data migration can occur between different layers of IT infrastructure environment  110  in order to optimize the placement of snapshots throughout the IT infrastructure environment. In one embodiment, hierarchical snapshot management program  200  can migrate snapshots to parent entities and layers of IT infrastructure environment  110 . For example, hierarchical snapshot management program  200  can migrate snapshots stored in storage devices on various layers of IT infrastructure environment  110  to a single parent layer. In exemplary embodiments, hierarchical snapshot management program  200  optimizes the placement of snapshots throughout IT infrastructure environment  110  by placing snapshots in certain layers of the IT infrastructure environment, minimizing storage space and complexity, and providing an increase in data security. In one embodiment, hierarchical snapshot management program  200  compares data of redundant, overlapping, or inconsistent snapshots to determine if snapshots are different from one another. Hierarchical snapshot management program  200  can remove the identical portions of the snapshots in order to consolidate the snapshots so that the snapshots are no longer redundant, overlapping, or inconsistent. In one embodiment, hierarchical snapshot management program  200  consolidates the redundant, overlapping, and inconsistent snapshots by generating updated snapshots not including unnecessary or repetitive information and removes snapshots having or including unnecessary or repetitive information. In another embodiment, hierarchical snapshot management program  200  can output a report detailing the identified redundant, overlapping, and inconsistent snapshots. In an exemplary embodiment, hierarchical snapshot management program  200  identifies the inconsistent snapshots (i.e., in a report), and allows for removal of the identified inconsistent snapshots. 
         [0026]    In an example, multiple snapshots in a certain area of IT infrastructure environment  110  exist and have been taken at different times. In such an example, a migration of the snapshots begins by assigning the oldest snapshot to a storage virtualizer of IT infrastructure environment  110  where hierarchical snapshot management program  200  creates and migrates a copy of the oldest snapshot to a storage device within IT infrastructure environment  110 . The migrated copy of the oldest snapshot has a timestamp indicating the time the oldest snapshot was created not when the copy was created. Once hierarchical snapshot management program  200  creates and migrates a copy of a snapshot, the original snapshot can be deleted. In this example, hierarchical snapshot management program  200  migrates a newer snapshot (a snapshot in the same area of IT infrastructure environment  110  but created at a later time) by assigning the newer snapshot to a storage virtualizer and associating the newer snapshot with the migrated copy of the oldest snapshot. Hierarchical snapshot management program  200  determines differential data between the newer snapshot and the migrated copy of the oldest snapshot, and data from the newer snapshot not included in the migrated copy of the oldest snapshot is added to the migrated copy of the oldest snapshot to create an updated snapshot. The updated snapshot has a timestamp indicating the time at which the newer snapshot was created. Since hierarchical snapshot management program  200  utilizes differential data between the oldest snapshot and the newest snapshot to create the updated current snapshot, the newer snapshot can be deleted. The migration process repeats for all snapshots (oldest to newest), and the result is hierarchical snapshot management program  200  generating a current snapshot for the certain area of IT infrastructure environment  110  from all previous snapshots of that area that hierarchical snapshot management program  200  can update with subsequent snapshots. 
         [0027]      FIG. 3  depicts a block diagram of components of computer  300 , which is representative of IT infrastructure environment  110 , I/O system  140 , and hierarchical snapshot manager  150 , in accordance with an illustrative embodiment of the present invention. It should be appreciated that  FIG. 3  provides only an illustration of one implementation and does not imply any limitations with regard to the environments in which different embodiments may be implemented. Many modifications to the depicted environment may be made. 
         [0028]    Computer  300  includes communications fabric  302 , which provides communications between computer processor(s)  304 , memory  306 , persistent storage  308 , communications unit  310 , and input/output (I/O) interface(s)  312 . Communications fabric  302  can be implemented with any architecture designed for passing data and/or control information between processors (such as microprocessors, communications and network processors, etc.), system memory, peripheral devices, and any other hardware components within a system. For example, communications fabric  302  can be implemented with one or more buses. 
         [0029]    Memory  306  and persistent storage  308  are computer readable storage media. In this embodiment, memory  306  includes random access memory (RAM)  314  and cache memory  316 . In general, memory  306  can include any suitable volatile or non-volatile computer readable storage media. Software and data  322  stored in persistent storage  308  for access and/or execution by processor(s)  304  via one or more memories of memory  306 . With respect to hierarchical snapshot manager  150 , software and data  322  includes hierarchical snapshot management program  200 . 
         [0030]    In this embodiment, persistent storage  308  includes a magnetic hard disk drive. Alternatively, or in addition to a magnetic hard disk drive, persistent storage  308  can include a solid-state hard drive, a semiconductor storage device, a read-only memory (ROM), an erasable programmable read-only memory (EPROM), a flash memory, or any other computer readable storage media that is capable of storing program instructions or digital information. 
         [0031]    The media used by persistent storage  308  may also be removable. For example, a removable hard drive may be used for persistent storage  308 . Other examples include optical and magnetic disks, thumb drives, and smart cards that are inserted into a drive for transfer onto another computer readable storage medium that is also part of persistent storage  308 . 
         [0032]    Communications unit  310 , in these examples, provides for communications with other data processing systems or devices. In these examples, communications unit  310  includes one or more network interface cards. Communications unit  310  may provide communications through the use of either or both physical and wireless communications links. Software and data  322  may be downloaded to persistent storage  308  through communications unit  310 . 
         [0033]    I/O interface(s)  312  allows for input and output of data with other devices that may be connected to computer  300 . For example, I/O interface(s)  312  may provide a connection to external device(s)  318 , such as a keyboard, a keypad, a touch screen, and/or some other suitable input device. External device(s)  318  can also include portable computer readable storage media such as, for example, thumb drives, portable optical or magnetic disks, and memory cards. Software and data  322  can be stored on such portable computer readable storage media and can be loaded onto persistent storage  308  via I/O interface(s)  312 . I/O interface(s)  312  also connect to a display  320 . 
         [0034]    Display  320  provides a mechanism to display data to a user and may be, for example, a computer monitor. Display  320  can also function as a touch screen, such as a display of a tablet computer. 
         [0035]    The programs described herein are identified based upon the application for which they are implemented in a specific embodiment of the invention. However, it should be appreciated that any particular program nomenclature herein is used merely for convenience, and thus the invention should not be limited to use solely in any specific application identified and/or implied by such nomenclature. 
         [0036]    The flowchart and block diagrams in the Figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods and computer program products according to various embodiments of the present invention. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s). It should also be noted that, in some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by special purpose hardware-based systems that perform the specified functions or acts, or combinations of special purpose hardware and computer instructions.