Method and system for adding redundancy to a continuous data protection system

• US 20050182910A1
• Filed: 02/04/2005
• Published: 08/18/2005
• Est. Priority Date: 02/04/2004
• Status: Abandoned Application

• Current Assignee: NetApp, Inc.
• Original Assignee: Alacritus, Inc. (NetApp, Inc.)
• Inventors: Chang, Yafen Peggy, Johnston, Craig Anthony, Trimmer, Donald Alvin, Stager, Roger Keith, Saxena, Pawan, Blaser, Rico
• Application Number:
  US11/051,862
• Publication Number:
  US 20050182910A1
• Time in Patent Office: Days
• US Class Current: 711/162
• 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 11/1461 Backup scheduling policy
• CPC Class Codes: G06F 11/1471 involving logging of persistent data for recovery
• CPC Class Codes: G06F 11/2076 Synchronous techniques

Abstract

A method for adding redundancy to a continuous data protection system begins by taking a snapshot of a primary volume at a specific point in time, in accordance with a retention policy. The snapshot is stored on a secondary volume, and the snapshot is cloned and stored on a third volume. The cloned snapshot is eventually expired according to a cloning policy.

Claims

1. A method for adding redundancy to a continuous data protection system, comprising the steps of:

taking a snapshot of a primary volume at a specific point in time;

storing the snapshot on a secondary volume;

cloning the snapshot and storing the cloned snapshot on a third volume;

expiring the cloned snapshot.

2. The method according to claim 1, wherein the taking step is performed according to a retention policy.

3. The method according to claim 1, wherein the cloning step is performed according to a cloning policy.

4. The method according to claim 3, wherein the cloning policy is part of a retention policy.

5. The method according to claim 3, wherein the cloning policy specifies at least one of:

a number of clones to be made, a frequency at which a clone is made, and a time period for retaining a clone.

6. The method according to claim 5, wherein the expiring step includes deleting the cloned snapshot at the end of the time period specified in the cloning policy.

7. The method according to claim 1, wherein the expiring step includes deleting the cloned snapshot at the same time as the snapshot.

8. The method according to claim 1, wherein the expiring step includes deleting the cloned snapshot at a different time than the snapshot.

9. The method according to claim 1, wherein the primary volume and the secondary volume are located within a first fault zone and the third volume is located in a second fault zone separate from the first fault zone.

10. A system for adding redundancy to a continuous data protection system, comprising:

snapshot means for taking a snapshot of a primary volume at a specific point in time;

storing means for storing said snapshot on a secondary volume;

cloning means for cloning said snapshot and storing said cloned snapshot on a third volume;

expiring means for expiring said cloned snapshot.

11. The system according to claim 10, wherein said snapshot means performs according to a retention policy.

12. The system according to claim 10, wherein said cloning means performs according to a cloning policy.

13. The system according to claim 12, wherein said cloning policy is part of a retention policy.

14. The system according to claim 12, wherein said cloning policy specifies at least one of:

a number of clones to be made, a frequency at which a clone is made, and a time period for retaining a clone.

15. The system according to claim 14, wherein said expiring means includes deleting said cloned snapshot at the end of said time period specified in said cloning policy.

16. The system according to claim 10, wherein said expiring means includes deleting said cloned snapshot at the same time as said snapshot.

17. The system according to claim 10, wherein said expiring means includes deleting said cloned snapshot at a different time than said snapshot.

18. The system according to claim 10, wherein said primary volume and said secondary volume are located within a first fault zone and said third volume is located in a second fault zone separate from said first fault zone.

19. A method for managing a recovery point in a continuous data protection system, comprising the steps of:

setting a retention policy;

taking a snapshot of a primary volume according to the retention policy, the snapshot providing a recovery point on the primary volume;

storing the snapshot on a secondary volume;

expiring the snapshot according to the retention policy;

setting a cloning policy;

creating a clone of the snapshot according to the cloning policy;

storing the cloned snapshot on a third volume; and

expiring the cloned snapshot according to the cloning policy.

20. The method according to claim 19, wherein the cloning policy is part of the retention policy.

21. The method according to claim 19, wherein the cloned snapshot is expired at the same time as the snapshot.

22. The method according to claim 19, wherein the cloned snapshot is expired at a different time than the snapshot.

23. A system for managing a recovery point in a continuous data protection system, comprising:

first policy means;

snapshot means for taking a snapshot of a primary volume, said first policy means controlling said snapshot means;

first storing means for storing said snapshot on a secondary volume;

first expiring means for expiring said snapshot, said first policy means controlling said first expiring means;

second policy means;

cloning means for creating a clone of said snapshot, said second policy means controlling said cloning means;

second storing means for storing said cloned snapshot on a third volume; and

second expiring means for expiring said cloned snapshot, said second policy means controlling said second expiring means.

24. The system according to claim 23, wherein:

said first policy means includes a retention policy; and

said second policy means includes a cloning policy.

25. The system according to claim 23, wherein said second policy means is part of said first policy means.

26. A system for continuous data protection, comprising:

a host computer;

a first volume connected to said host computer, said first volume containing data to be protected;

a first data protection system connected to said host computer;

a second volume connected to said first data protection system, said second volume being a protected version of said first volume;

a second data protection system communicating with said first data protection system; and

a third volume connected to said second data protection system, said third volume being a copy of said second volume.

27. The system according to claim 26, wherein said first data protection system and said second data protection system communicate asynchronously.

28. The system according to claim 26, wherein said second data protection system and said third volume are located in a fault zone with said first data protection system and said second volume.

29. The system according to claim 26, wherein said second data protection system and said third volume are located in a fault zone separate from said first data protection system and said second volume.

30. The system according to claim 26, further comprising:

a third data protection system communicating with said second data protection system; and

a fourth volume connected to said third data protection system, said fourth volume being a copy of said third volume.

31. The system according to claim 30, wherein

said second data protection system communications with said first data protection system synchronously, whereby said third volume is a current copy of said second volume;

and

said third data protection system communicates with said second data protection asynchronously.

32. The system according to claim 30, wherein

said second data protection system and said third volume are located in a first fault zone with said first data protection system and said second volume;

and

said third data protection system and said fourth volume are located in a second fault zone, said second fault zone being separate from said first fault zone.

33. The system according to claim 30, wherein

said first data protection system and said second volume are located in a first fault zone;

said second data protection system and said third volume are located in a second fault zone, said second fault zone being separate from said first fault zone; and

said third data protection system and said fourth volume are located in a third fault zone, said third fault zone being separate from said first fault zone and said second fault zone.