Method and apparatus for data backup using data blocks

• US 7,814,056 B2
• Filed: 01/13/2006
• Issued: 10/12/2010
• Est. Priority Date: 05/21/2004
• Status: Active Grant

• Current Assignee: Computer Associates Think Inc. (Broadcom, Inc.)
• Original Assignee: Computer Associates Think Inc. (Broadcom, Inc.)
• Inventors: Ball, Stephen, McGrattan, Emma K., Yang, Frank H., Moucaddem, Sami R., Rivet, Jean-Francois, Kuo, Chin L.
• Primary Examiner(s): Truong; Cam Y
• Assistant Examiner(s): Pham; Michael
• Application Number:
  US11/331,615
• Publication Number:
  US 20070027937A1
• Time in Patent Office: 1,733 Days
• Field of Search: None
• US Class Current: 707/640
• CPC Class Codes: G06F 11/1451 by selection of backup contents
• CPC Class Codes: G06F 11/1456 Hardware arrangements for backup
• CPC Class Codes: G06F 11/1458 Management of the backup or restore process
• CPC Class Codes: G06F 11/1469 Backup restoration techniques
• CPC Class Codes: G06F 2201/80 Database-specific techniques
• CPC Class Codes: G06F 2201/83 the solution involving signatures
• CPC Class Codes: G06F 2201/835 Timestamp

Abstract

Methods and apparatuses for backing up data to a database are provided. A specified data set to be backed up is broken down into a plurality of data blocks, each data block is associated with a data block digest, and the data blocks and associated data block digests are stored in the database. When one or more data blocks are subsequently changed, an update to the backup may be performed by adding to the backup data only the data blocks that have changed since the initial backup. Methods and apparatuses for restoring backup data from a database are also provided. Timestamp information associated with the data blocks in the database is used to select the data blocks to be restored.

Claims

1. A method for backing up data, comprising:

at a first computer;

breaking down a specified data set to be backed up into a plurality of data blocks;

generating for each data block a corresponding data block digest and associated metadata comprising data block information; and

associating each data block digest and associated metadata with the corresponding data block; and

comparing a first generated data block digest for a selected data block in the specified data set to be backed up with data block digests stored in a remote database storage device and associated with backed up data blocks stored in the remote database storage device to determine whether the selected data block is already backed up;

upon determining that the first generated data block digest is not equal to any of the data block digests of the backed up data blocks stored in the remote database storage device, storing the selected data block, the associated first generated data block digest, and the associated metadata in the remote database storage device, wherein storing the associated metadata comprises storing in the remote database storage device at least one timestamp associated with the selected data block in the specified data set to be backed up; and

upon determining that the first generated data block digest is equal to one of the data block digests of the backed up data blocks stored in the remote database storage device, updating metadata associated with the data block already stored in the remote database storage device with the generated metadata, wherein updating metadata associated with the data block already stored in the remote database storage device with the generated metadata comprises updating the at least one timestamp associated with the data block already stored in the remote database storage device with the generated metadata.

2. The method of claim 1, further comprising refreshing backup of the specified data set after the data set has been backed up.

3. The method of claim 2, wherein the refreshing backup of the specified data set includes determining a new data block digest of the selected data block in the specified data set to be refreshed, comparing the new data block digest of the selected data block to the stored data block digest of the associated data block in the remote database storage device which corresponds to the selected data block, and backing up the selected data block and new data block digest in the remote database storage device if the new data block digest of the selected data block does not equal the stored data block digest of the associated data block in the remote database storage device.

4. The method of claim 3, wherein if the selected data block in the specified data set is backed up in the remote database storage device, the selected data block replaces the associated data block in the remote database storage device as a current version of the data block.

5. The method of claim 1, wherein the data blocks have a fixed size per object set.

6. The method of claim 1, wherein the data to be backed up is pre-selected by a user and arranged into an object set.

7. The method of claim 6, wherein the object set is referenced by a set identifier.

8. The method of claim 6, wherein the object set comprises a plurality of data objects.

9. The method of claim 8, wherein each data object has an associated object identifier and object name.

10. The method of claim 8, wherein an object instance of a data object includes an object identifier, timestamp and attribute information.

11. The method of claim 10, wherein the attribute information of the object instance is stored in the remote database storage device.

12. The method of claim 10, wherein the object identifier and the timestamp of the object instance are stored as metadata in a database catalog.

13. The method of claim 8, wherein an object map is generated for a data object, and the object map includes object identifier, timestamp, data block number, block identifier and data block digest information.

14. The method of claim 13, wherein the data block digest information and the data block number information are stored in the remote database storage device.

15. The method of claim 13, wherein the object identifier information, timestamp and block identifier information are stored as metadata in a database catalog.

18. The method of claim 13, further comprising deleting a data object when requested, wherein the data object is flagged as deleted in a database catalog, and data blocks and the object map corresponding to the data object remain in the remote database storage device until requested to be permanently deleted.

19. The method of claim 1, further comprising updating a backup of the specified data set after the data set has been backed up.

20. The method of claim 1, further comprising:

receiving specification of a time to which data restoration is desired;

comparing the specified time to the at least one timestamp stored for each data block of the backup data in the remote database storage device; and

retrieving a stored data block of the backup data, if the stored data block has an associated timestamp at or earlier than the specified time and no other data blocks of the backup data which correspond to the stored data block have more contemporaneous timestamps between the specified time and the associated timestamp of the stored data block.

21. The method of claim 20, wherein the at least one timestamp is retrieved from a database catalog.

22. The method of claim 20, wherein the backup data is retrieved from the remote database storage device.

23. The method of claim 20, further comprising backing up the restored backup data to a secondary backup medium.

24. The method of claim 1, further comprising:

retrieving the at least one timestamp for a group of corresponding data blocks in the backup data from a database catalog;

comparing the at least one timestamp for the data blocks in the group;

selecting a recent data block in the group having the most recent timestamp as compared to the other corresponding data blocks in the group; and

restoring the recent data block having the most recent timestamp.

25. The method of claim 24, further comprising, grouping each of the data blocks with the most recent timestamp by object set, and ordering each data block within each object set by block number.

30. The method of claim 1, further comprising:

at a second computer remote from the first computer and the remote database storage device;

breaking down a second version of the specified data set to be backed up into a second plurality of data blocks comprising at least the selected data block;

generating for each of the second plurality of data blocks a corresponding data block digest and metadata; and

associating each data block digest and each metadata with the corresponding data block; and

comparing a second generated data block digest for the selected data block of the second version of the specified data set to be backed up with the first generated data block digest stored in the remote database storage device to determine whether the selected data block is already backed up;

upon determining that the second generated data block digest is not equal to the first generated data block digest stored in the remote database storage device, storing the selected data block, the associated second generated data block digest, and the associated metadata in the remote database storage device.

16. A computer system comprising:

a remote database storage device comprising a non-transitory storage medium; and

a processor coupled to the remote database storage device and configured to;

break down a specified data set to be backed up into a plurality of data blocks;

generate for each data block a corresponding data block digest and associated metadata comprising data block information;

associate each data block digest and associated metadata with the corresponding data block; and

compare a first generated data block digest for a selected data block in the specified data set to be backed up with data block digests stored in the remote database storage device and associated with backed up data blocks stored in the remote database storage device to determine whether the selected data block is already backed up; and

an interface coupled to the central processing unit (CPU) and configured to transmit the data block, the associated first generated data block digest, and the associated metadata to the remote database storage device, wherein;

upon determining that the first generated data block is not equal to any of the data block digests of the backed up data blocks stored in the remote database storage device, the remote database storage device is configured to store therein the data block, the associated first generated data block digest, and the associated metadata, wherein the associated metadata comprises at least one timestamp associated with the selected data block in the specified data set to be backed up; and

upon determining that the first generated data block digest is equal to one of the data block digests of the backed up data blocks stored in the remote database storage device, the remote database storage device is configured to update metadata associated with the data block already stored in the remote database storage device with the generated metadata, wherein updating metadata associated with the data block already stored in the remote database storage device with the generated metadata comprises updating the at least one timestamp associated with the data block already stored in the remote database storage device with the generated metadata.

26. The computer system of claim 16, wherein the processor is further configured to:

receive specification of a time to which data restoration is desired; and

compare the specified time to the at least one timestamp stored for each data block of the backup data in the remote database storage device; and

retrieve a stored data block of the backup data, if the stored data block has an associated timestamp at or earlier than the specified time and no other data blocks of the backup data which correspond to the stored data block have more contemporaneous timestamps between the specified time and the associated timestamp of the stored data block.

27. The computer system of claim 16, wherein the processor is further configured to:

retrieve the at least one timestamp for a group of corresponding data blocks in the backup data from a database catalog;

compare the at least one timestamp for the data blocks in the group;

select a recent data block in the group having the most recent timestamp as compared to the other corresponding data blocks in the group; and

restore the recent data block having the most recent timestamp.

17. A non-transitory storage medium readable by a machine and tangibly embodying a program of instructions executable by the machine, when executed the program of instructions configured to:

at a first computer;

break down a specified data set to be backed up into a plurality of data blocks;

generate for each data block a corresponding data block digest and associated metadata comprising data block information; and

associate each data block digest and associated metadata with the corresponding data block; and

compare a first generated data block digest for a selected data block in the specified data set to be backed up with data block digests stored in a remote database storage device and associated with backed up data blocks stored in the remote database storage device to determine whether the selected data block is already backed up;

upon determining that the first generated data block digest is not equal to any of the data block digests of the backed up data blocks stored in the remote database storage device, store the data block, the associated first generated data block digest, and the associated metadata in the remote database storage device, wherein storing the associated metadata comprises storing in the remote database storage device at least one timestamp associated with the selected data block in the specified data set to be backed up; and

upon determining that the first generated data block digest is equal to one of the data block digests of the backed up data blocks stored in the remote database storage device, update metadata associated with the data block already stored in the remote database storage device with the generated metadata, wherein updating metadata associated with the data block already stored in the remote database storage device with the generated metadata comprises updating the at least one timestamp associated with the data block already stored in the remote database storage device with the generated metadata.

28. The program storage device of claim 17, wherein the instructions further configured to:

receive specification of a time to which data restoration is desired;

compare the specified time to the at least one timestamp stored for each data block of the backup data in the remote database storage device; and

retrieve a stored data block of the backup data, if the stored data block has an associated timestamp at or earlier than the specified time and no other data blocks of the backup data which correspond to the stored data block have more contemporaneous timestamps between the specified time and the associated timestamp of the selected data block.

29. The non-transitory storage medium of claim 17, wherein the instructions further configured to:

retrieve the at least one timestamp for a group of corresponding data blocks in the backup data from a database catalog;

compare the at least one timestamp for the data blocks in the group;

select a recent data block in the group having the most recent timestamp as compared to the other corresponding data blocks in the group; and

restore the recent data block having the most recent timestamp.