Systems and methods for providing a modification history for a location within a data store

• US 7,287,133 B2
• Filed: 08/24/2004
• Issued: 10/23/2007
• Est. Priority Date: 08/24/2004
• Status: Active Grant

• Current Assignee: Veritas Technologies, LLC (Whitehouse Group Ltd.)
• Original Assignee: Symantec Operating Corporation (Gen Digital Inc.)
• Inventors: Rowan, Michael, Rodgers, Kevin
• Primary Examiner(s): NGUYEN, THAN VINH
• Application Number:
  US10/924,669
• Publication Number:
  US 20060047895A1
• Time in Patent Office: 1,155 Days
• Field of Search: None
• US Class Current: 711/156
• CPC Class Codes: G06F 11/0727 in a storage system, e.g. in a DASD or network based storage system drivers for digital recording or reproducing units G06F3/06; circuits for error detection or correction within digital recording or reproducing units G11B20/18; for distributed storage of data in networks, e.g. transport arrangements for network file system [NFS], storage area networks [SAN] or network attached storage [NAS], H04L67/1097
• CPC Class Codes: G06F 11/0751 Error or fault detection not based on redundancy power supply failures G06F1/30; network fault management H04L41/06
• CPC Class Codes: G06F 11/1469 Backup restoration techniques
• CPC Class Codes: G06F 11/1474 in transactions G06F16/20 takes precedence
• CPC Class Codes: G06F 2201/82 Solving problems relating to consistency
• CPC Class Codes: G06F 2201/84 Using snapshots, i.e. a logical point-in-time copy of the data

Abstract

A storage management device can receive a request for a modification history for a location within a data store, determine one or more times at which at least a portion of data stored at the location was modified, and transmit the one or more determined times.

Claims

1. A method for providing a modification history for a location within a data store, the method comprising:

intercepting all write requests directed to a data store on a continuous basis without scheduling any volume-level snapshot, wherein a copy-on-write operation is performed in response to each write request, thereby generating a historical index of copy-on-write operations;

receiving-a request for a modification history for a specified location within the data store;

determining at least one time at which at least a portion of data stored at the specified location was modified, the determination being based on the historical index of copy-on-write operations; and

transmitting, in response to the received request, the at least one determined time.

2. The method of claim 1 wherein the specified location comprises an address range within the data store.

3. The method of claim 2 wherein the address range comprises a logical block address and a length.

4. The method of claim 3 wherein the logical block address specifies a beginning of the address range.

5. The method of claim 1 wherein the request for the modification history is received in a packet.

6. The method of claim 5 wherein the packet comprises at least a portion of an input/output command.

7. The method of claim 6 wherein the input/output command is in a standard input/output command format.

8. The method of claim 7 wherein the input/output command is a Small Computer Systems Interf ace (SCSI) command.

9. The method of claim 1 wherein the determining step comprises determining at least one time at which a subset of the data stored at the specified location was modified.

10. The method of claim 1 wherein the determining step comprises determining at least one time at which all of the data stored at the specified location was modified.

11. The method of claim 1 wherein the determining step comprises determining at least one time at which a superset of the data stored at the specified location was modified.

12. The method of claim 1 wherein the at least one time comprises at least two times.

13. The method of claim 1 wherein the at least one time comprises one time.

14. The method of claim 1 further comprising identifying for each determined time, an address range within the data store at which data was modified at that determined time.

15. The method of claim 14 wherein the at least one identified address range comprises at least a portion of the specified location.

16. The method of claim 14 wherein the at least one identified address range comprises a superset of the specified location.

17. The method of claim 14 further comprising transmitting in response to the received request, the at least one identified address range.

18. The method of claim 17 wherein the at least one determined time and the at least one identified address range are transmitted in a single packet.

19. The method of claim 18 wherein the transmitted packet comprises at least one tuple, each tuple comprising one determined time and the address range identified for that determined time.

20. The method of claim 19 wherein the transmitted packet indicates the number of tuples comprised within the packet.

21. The method of claim 18 wherein the single packet is transmitted to a host.

22. The method of claim 14 wherein the at least one address range comprises a logical block address and a length.

23. The method of claim 22 wherein the logical block address specifies a beginning of the at least one address range.

24. The method of claim 1 wherein the determined time is an absolute time.

25. The method of claim 1 wherein the determined time is a time relative to a present time.

26. A storage management device for providing a modification history for a location within a data store, the storage management device comprising:

a data backup module to intercept all write requests directed to a data store on a continuous basis without scheduling any volume-level snapshot, wherein a copy-on-write operation is performed in response to each write request, thereby generating a historical index of copy-on-write operations;

a receiver to receive a request for a modification history for a specified location within the data store;

a determination module to determine at least one time at which at least a portion of data stored at the specified location was modified, the determination being based on the historical index of copy-on-write operations; and

a transmitter to transmit, in response to the received request, the at least one determined time.

27. An article of manufacture for providing a modification history for a location within a data store, the article of manufacture comprising:

at least one processor readable medium; and

instructions carried on the at least one medium;

wherein the instructions are configured to be readable from the at least one medium by at least one processor and thereby cause the at least one processor to operate so as to;

intercept all write requests directed to a data store on a continuous basis without scheduling any volume-level snapshot, wherein a copy-on-write operation is performed in response to each write request, thereby generating a historical index of copy-on-write operations;

receive a request for a modification history for a specified location within &

the data store;

determine at least one time at which at least a portion of data stored at the specified location was modified, the determination being based on the historical index of copy-on-write operations; and

transmit, in response to the received request, the at least one determined time.

28. A method for responding to a request for a modification history for a location within a data store, the method comprising:

intercepting all write requests directed to a data store on a continuous basis without scheduling any volume-level snapshot, wherein a copy-on-write operation is performed in response to each write request, thereby generating a historical index of copy-on-write operations;

generating, in response to a request for a modification history for a specified location within the data store, a data packet containing at least one tuple, the tuple comprising;

an address range identifying the location of one or more units of storage within a the data store at which data was modified at a determined time; and

the determined time; and

transmitting the data packet.

29. The method of claim 28, wherein the data packet further comprises an indicator indicating the number of tuples comprised within the data packet.

30. The method of claim 28 wherein the determined time is an absolute time.

31. The method of claim 28 wherein the determined time is a time relative to a present time.