System and method for performing a snapshot and for restoring data

• US 7,529,782 B2
• Filed: 11/15/2004
• Issued: 05/05/2009
• Est. Priority Date: 11/13/2003
• Status: Active Grant

• Current Assignee: CommVault Systems Incorporated
• Original Assignee: CommVault Systems Incorporated
• Inventors: Ngo, David, Prahlad, Anand, Pawar, Rahual, Varadharajan, Prakash, Kumar, Avinash
• Primary Examiner(s): Breene; John E
• Assistant Examiner(s): Kerzhner; Aleksandr
• Application Number:
  US10/990,336
• Publication Number:
  US 20050187992A1
• Time in Patent Office: 1,632 Days
• Field of Search: None
• US Class Current: 1/1
• 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 present invention relates to a method for tracking a plurality of snapshots of an information store. The present invention comprises performing 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 computer-readable storage medium whose stored contents cause a data storage system to perform a method of tracking a plurality of representations of a data store at various points in time, the method comprising:

creating a first representation of a data store at a first time, wherein the first representation includes information identifying a first set of data objects within the data store at the first time and locations of the identified first set of data objects at the first time;

copying the identified first set of data objects and the first representation of the data store to a location remote from the location of the data store;

creating a second representation of the data store at a second time after the first time, wherein the second representation includes information identifying a second set of data objects within the data store at the second time and locations of the identified second set of data objects at the second time;

comparing the first representation to the second representation to identify data objects that changed from the initial time to the second time;

creating a data structure mapping the changed data objects to portions of the representations of the data store that identify the locations of the changed data objects;

copying the created data structure and the changed data objects to a location remote from the data store;

wherein the data structure maps the changed data objects to individual data blocks storing the changed data objects.

2. The computer-readable medium of claim 1, wherein the data structure also maps the changed data objects to clusters storing the changed data objects.

3. A method in a computing system for tracking snapshots taken of a volume of data, wherein a snapshot is a point-in-time representation of the volume of data, the method comprising:

creating a first snapshot stored in a memory of a computer of the volume of data, wherein the first snapshot includes information identifying data objects within the volume of data at a first time and information identifying a location of the identified data objects at the first time;

mapping the data objects within the volume of data to the first snapshot, wherein the mapping includes updating a first data structure that contains entries associating data objects with corresponding portions of the first snapshot that include the information identifying the location of the identified data objects at the first time;

creating a second snapshot stored in a memory of a computer of the volume of data, wherein the second snapshot includes information identifying data objects within the volume of data at a second time after the first time and information identifying a location of the identified data objects at the second time;

comparing the first snapshot with the second snapshot to determine data objects that changed after the first time;

mapping the changed data objects to the second snapshot, wherein the mapping the changed data objects includes updating a second data structure that includes entries associating the changed data objects with corresponding portions of the second snapshot that include the information identifying the location of the changed data objects at the second time;

copying the changed data objects and the second snapshot of the volume of data to a location remote from the volume of data;

wherein mapping the data objects within the volume of data to the snapshots includes mapping individual files or folders within the volume of data to corresponding portions of the snapshots.

4. The method of claim 3, further comprising:

copying the data objects within the volume of data at the first time and the first snapshot of the volume of data to a location remote from the volume of data.

5. The method of claim 3, wherein mapping the data objects within the volume of data to the snapshots also includes mapping data blocks of the volume of data to corresponding portions of the snapshots.

6. The method of claim 3, wherein mapping the data objects within the volume of data to the snapshots also includes mapping clusters of the volume of data to corresponding portions of the snapshots.

7. The method of claim 3, further comprising:

presenting a data object restoration interface to a user, wherein the data object restoration interface identifies user-selectable options for restoring the volume of data at multiple points in time;

receiving a selection from the user to restore one or more data objects from a previous point in time of the volume of data;

restoring snapshots that include information identifying the one or more data objects; and

overwriting portions of the snapshots created before the restored point-in-time restoration that include information identifying the one or more data objects.

8. The method of claim 3, further comprising:

presenting a data object restoration interface to a user, wherein the data object restoration interface identifies user-selectable options for restoring the volume of data at multiple points in time;

receiving a selection from the user to restore one or more data objects from a previous point in time of the volume of data; and

determining portions of the snapshots that correspond to the selected one or more data objects; and

restoring the determined portions.