System and method for performing a snapshot and for restoring data

• US 8,195,623 B2
• Filed: 03/20/2009
• Issued: 06/05/2012
• Est. Priority Date: 11/13/2003
• Status: Active Grant

• Current Assignee: CommVault Systems Incorporated
• Original Assignee: CommVault Systems Incorporated
• Inventors: Prahlad, Anand, Ngo, David, Varadharajan, Prakash, Pawar, Rahul, Kumar, Avinash
• Primary Examiner(s): Kerzhner, Aleksandr
• Application Number:
  US12/407,906
• Publication Number:
  US 20090182963A1
• Time in Patent Office: 1,173 Days
• Field of Search: 707/679, 707/999.202
• US Class Current: 707/679
• CPC Class Codes: G06F 11/1435 using file system or storage system metadata
• CPC Class Codes: G06F 11/1446 Point-in-time backing up or restoration of persistent data
• CPC Class Codes: G06F 11/1448 Management of the data involved in backup or backup restore
• CPC Class Codes: G06F 11/1469 Backup restoration techniques
• CPC Class Codes: G06F 16/128 Details of file system snapshots on the file-level, e.g. snapshot creation, administration, deletion use of snapshots for error detection or correction G06F11/14, G06F11/16
• CPC Class Codes: G06F 16/178 Techniques for file synchronisation in file systems
• CPC Class Codes: G06F 16/1844 Management specifically adapted to replicated file systems
• CPC Class Codes: G06F 16/22 Indexing; Data structures therefor; Storage structures
• CPC Class Codes: G06F 16/285 Clustering or classification
• CPC Class Codes: G06F 16/86 Mapping to a database
• CPC Class Codes: G06F 2201/80 Database-specific techniques
• CPC Class Codes: G06F 2201/805 Real-time
• CPC Class Codes: G06F 2201/84 Using snapshots, i.e. a logical point-in-time copy of the data
• CPC Class Codes: Y10S 707/99944 Object-oriented database structure
• CPC Class Codes: Y10S 707/99952 Coherency, e.g. same view to multiple users
• CPC Class Codes: Y10S 707/99953 Recoverability
• CPC Class Codes: Y10S 707/99955 Archiving or backup

Abstract

The system and method are used for tracking a plurality of snapshots of an information store. The system performs a first snapshot of an information store that indexes the contents of the information store, copying the contents of the information store to a first storage device, using the first snapshot, and updating a replication volume table indicating the storage of the contents of the first information store using the first snapshot on the first storage device. A second snapshot is performed of the information store that indexes the contents of the information store, the contents of the information store are copied to a second storage device using the second snapshot and the replication volume table is updated to indicate the storage of the contents of the first information store using the second snapshot on the second storage device.

Claims

1. A method performed by one or more computing systems, each computing system having a processor and memory, of restoring data, the method comprising:

receiving, via a user interface, a selection of a given point in time to which to restore a portion of an information store on at least one first storage device, wherein multiple snapshots have been made of the information store prior to or near to the given point in time, and wherein the snapshots are stored on at least one remote storage device that is remotely located from the first storage device and wherein snapshots taken after an initial snapshot comprise;

changed data from at least one storage block of the information store, wherein the changed data contains data that has been changed or created since the time a most-recently made previous snapshot was created,

a first data structure identifying the at least one storage block,

a second data structure indicating a physical location of the changed data within the remote storage device,

a third data structure mapping the at least one storage block to one or more files associated with the changed data, and

a fourth data structure identifying a previous snapshot containing data from the at least one storage block;

identifying a first set of two or more snapshots, wherein each snapshot in the first set indexes storage blocks associated with the portion of the information store to be restored;

determining a most-recently made snapshot in the first set necessary to restore the portion of the information store;

determining one or more snapshots in the first set, other than the most-recently made snapshot, necessary to restore the portion of the information store;

restoring, by the one or more computer systems, storage blocks associated with the portion of the information store that are indexed by the most-recently made snapshot; and

after restoring the storage blocks associated with the portion of the information store that are indexed by the most-recently made snapshot, restoring, by the one or more computer systems, storage blocks that are not already restored and that are associated with the portion of the information store indexed by the one or more other snapshots,

wherein the restoring is performed in reverse chronological order of times at which the one or more other snapshots were made, and

wherein the determining a most-recently made snapshot and the determining one or more snapshots in the first set includes reviewing the at least one snapshot to identify changed blocks or files within the information store.

2. The method of claim 1, further comprising:

accessing the most-recently made snapshot;

determining the storage blocks associated with the portion of the information store that are indexed by the most-recently made snapshot;

accessing the one or more other snapshots, and

determining the not already restored storage blocks associated with the portion of the information store that are indexed by the one or more other snapshots.

3. The method of claim 1, wherein the storage units associated with the portion of the information store that are indexed by the most-recently made snapshot are stored on a first storage device, wherein the not already restored storage blocks are stored on one or more second storage devices, and wherein the method further comprises:

accessing the first storage device;

obtaining from the first storage device the storage blocks associated with the portion of the information store that are indexed by the most-recently made snapshot;

accessing the one or more second storage devices; and

obtaining from the one or more second storage devices the storage blocks associated with the portion of the information store that are indexed by the one or more other snapshots.

4. The method of claim 1, wherein the multiple snapshots and storage blocks indexed by the multiple snapshots are stored on multiple storage devices across a data storage network.

5. The method of claim 1, wherein the storage blocks are either clusters, blocks, or extents.

6. The method of claim 1, wherein the portion of an information store is either multiple files and/or folders or the entire information store.

7. The method of claim 1, further comprising accessing a data structure that expresses or implies the chronological order of times at which the two or more snapshots in the first set were made.

8. The method of claim 1, wherein the information store includes multiple files and/or folders, the information store is associated with a data structure that includes information associated with the multiple files and/or folders, at least a portion of the information is stored in association with the two or more snapshots in the first set, and wherein the method further comprises:

accessing the at least portion of the information;

presenting to a user the at least portion of the information in a graphical user interface; and

receiving from the user via the graphical user interface a selection of one or more of the multiple files and/or folders to restore.

9. A system for restoring data, the system comprising:

a processor;

memory;

means for receiving a selection of a given point in time to which to restore a portion of an information store on at least one first storage device, wherein multiple snapshots have been made of the information store prior to or near to the given point in time, and wherein the snapshots are stored on at least one remote storage device that is remotely located from the first storage device and comprise;

changed data from at least one storage block of the information store, wherein the changed data contains data that has been changed or created since the time a most-recently made previous snapshot was created,

a first data structure identifying the at least one storage block,

a second data structure indicating a physical location of the changed data within the remote storage device,

a third data structure mapping the at least one storage block to one or more files associated with the changed data, and

a fourth data structure identifying a previous snapshot containing data from the at least one storage block;

means for identifying a first set of two or more snapshots, wherein each snapshot in the first set indexes storage blocks associated with the portion of the information store to be restored;

means for determining a most-recently made snapshot in the first set necessary to restore the portion of the information store;

means for determining one or more snapshots in the first set, other than the most-recently made snapshot, necessary to restore the portion of the information store;

means for restoring, by the one or more computer systems, storage blocks associated with the portion of the information store that are indexed by the most-recently made snapshot; and

means for after restoring the storage blocks associated with the portion of the information store that are indexed by the most-recently made snapshot, restoring, by the one or more computer systems, storage blocks that are not already restored and that are associated with the portion of the information store indexed by the one or more other snapshots,

wherein the restoring is performed in reverse chronological order of times at which the one or more other snapshots were made, and

wherein the means for determining a most-recently made snapshot or the means for determining one or more snapshots in the first set includes means for reviewing the at least one snapshot to identify changed blocks or files within the information store.

10. The system of claim 9, further comprising:

means for accessing the most-recently made snapshot;

means for determining the storage blocks associated with the portion of the information store that are indexed by the most-recently made snapshot;

means for accessing the one or more other snapshots, and

means for determining the not already restored storage blocks associated with the portion of the information store that are indexed by the one or more other snapshots.

11. The system of claim 9, wherein the storage blocks are clusters, blocks, or extents.

12. The system of claim 9, wherein the portion of an information store is either multiple files and/or folders or the entire information store.

13. The system of claim 9, further comprising accessing a data structure that expresses or implies the chronological order of times at which the two or more snapshots in the first set were made.

14. A system for restoring a file or folder from a data store indexed by snapshots at various points in time, the system comprising:

a presentation component, wherein the presentation component presents a user with indications of files or folders from a data store on at least one first storage device to be restored;

an input component, wherein the input component receives user input selecting a file or folder to be restored;

a retrieval component comprising one or more computer processors and configured to retrieve, one or more snapshots stored in at least one second storage device that is distinct and remotely located from the first storage device, wherein snapshots taken after an initial snapshot include;

changed data from at least one storage block of the at least one first storage device wherein the changed data contains data that has been changed or created since the time a most-recently taken previous snapshot was created,

at least a first data structure identifying the at least one storage block,

a second data structure indicating a physical location of the changed data within the at least one second storage device,

a third data structure mapping the at least one storage block to one or more files associated with the changed data, and

a fourth data structure identifying a previous snapshot containing data from the at least one storage block;

a restoration component, wherein

the restoration component reviews a data structure stored on the second storage device that maps portions of the one or more snapshots stored in the second storage device to files or folders of the data store on the first storage device,

identifies a portion of the one or more snapshots mapped to the selected files or folders, and

restores the identified portion of the one or more snapshots, wherein the restoring includes;

restoring a most-recently made snapshot associated with a first portion of a user selected file or folder to be restored, and

restoring one or more other snapshots associated with a second portion of the user selected file or folder, wherein the restoring is performed in reverse chronological order of times at which the one or more other snapshots were made.

15. The system of claim 14, wherein the reviewed data structure maps clusters storing the portions of the one or more snapshots to files or folders of the data store.

16. The system of claim 14, wherein the reviewed data structure maps data blocks storing the portions of the one or more snapshots to files or folders of the data store.

17. The system of claim 14, wherein the snapshots are stored in locations remote from the data structure.