System and method for fault-tolerant synchronization of replica updates for fixed persistent consistency point image consumption

• US 7,363,537 B1
• Filed: 12/15/2006
• Issued: 04/22/2008
• Est. Priority Date: 12/23/2003
• Status: Active Grant

• Current Assignee: Network Appliance Incorporated (NetApp, Inc.)
• Original Assignee: Network Appliance Incorporated (NetApp, Inc.)
• Inventors: Manley, Stephen L., Svarcas, Rimas
• Primary Examiner(s): Chu; Gabriel
• Application Number:
  US11/639,929
• Time in Patent Office: 494 Days
• Field of Search: 714/15, 714/19, 714/20, 714/21
• US Class Current: 714/15
• CPC Class Codes: G06F 11/1451 by selection of backup contents
• CPC Class Codes: G06F 11/2074 Asynchronous 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 2201/84 Using snapshots, i.e. a logical point-in-time copy of the data

Abstract

A method and apparatus for operating a storage system is disclosed. A root node has a first pointers to a plurality of lower nodes, the lower nodes having reference through a plurality of second pointers to point to blocks of persistent storage, the blocks of persistent storage storing data of the storage system. A persistent consistency point of the storage system is created at a selected time, the persistent consistency point created by creating a partial consistency point for one or more of the first pointers and second pointers to selected blocks of data. A statutes indicator is set to indicate that an identified partial consistency point is completed. All partial consistency points are coalesced into a final completed consistency point for the selected time after all of the partial consistency points reach a status of completed.

Claims

1. A method for operating a storage system, comprising:

maintaining a root node having first pointers to a plurality of lower nodes, the lower nodes having reference through a plurality of second pointers to point to blocks of persistent storage, the blocks of persistent storage storing data of the storage system;

creating a persistent consistency point of the storage system at a selected time, the persistent consistency point created by creating a partial consistency point for one or more of the first pointers and second pointers to selected blocks of data;

setting a status indicator to indicate that an identified partial consistency point is completed; and

coalescing all partial consistency points into a final completed consistency point for the selected time after all of the partial consistency points reach a status of completed.

2. The method as in claim 1, further comprising:

saving the final completed consistency point in persistent storage by an operating system of a computer maintaining the storage system.

3. The method as in claim 1, further comprising:

transferring data of the final completed consistency point over a computer network to a target computer; and

saving the final completed consistency point in persistent storage by the target computer.

4. The method as in claim 1, further comprising:

rolling back a partial consistency point in response to a failure in transferring partial consistency point data to a persistent storage.

5. The method as in claim 1,

wherein the root node comprises a root inode.

6. The method as in claim 1,

wherein the lower nodes comprise inodes.

7. The method as in claim 1,

wherein the first pointers and the plurality of second pointers comprise qtrees.

8. The method as in claim 1,

wherein the first pointers and the plurality of second pointers comprise a volume.

9. The method as in claim 1,

wherein the first pointers and the plurality of second pointers comprise a sub-volume.

10. The method as in claim 1,

wherein the first pointers and the plurality of second pointers comprise a sub-group in a volume.

11. The method as in claim 1, further comprising:

wherein the first pointers and the plurality of second pointers comprise a sub-tree in a volume'"'"'s file system.

12. The method as in claim 1, further comprising:

wherein the first pointers and the plurality of second pointers comprise a volume sub-organization.

13. A method for operating a storage system, comprising:

maintaining a root node having first pointers to a plurality of lower nodes, the lower nodes having reference through a plurality of second pointers to point to blocks of persistent storage, the blocks of persistent storage storing data of the storage system; and

creating a persistent consistency point of the storage system at a selected time, the persistent consistency point created by creating a partial consistency point for one or more of the first pointers and second pointers to selected blocks of data.

14. The method of claim 13, further comprising:

setting a status indicator to indicate that an identified partial consistency point is completed; and

coalescing all partial consistency points into a final completed consistency point for the selected time after all of the partial consistency points reach a status of completed.

15. A method for operating a storage system, comprising:

maintaining a root node having first pointers to a plurality of lower nodes, the lower nodes having reference through a plurality of second pointers to blocks of persistent storage storing data of the storage system;

identifying a sub-organization of the pointers;

creating a persistent consistency point of the storage system at a selected time, the persistent consistency point created by creating a partial consistency point for one or more of the sub-organizations of pointers;

setting a status indicator to indicate that an identified partial consistency point is completed; and

coalescing all partial consistency points into a final completed consistency point for the selected time after all of the partial consistency points reach a status of completed.

16. A storage system, comprising:

a root node having first pointers to a plurality of lower nodes, the lower nodes having reference through a plurality of second pointers to point to blocks of persistent storage, the blocks of persistent storage storing data of the storage system;

a persistent consistency point of the storage system created at a selected time, the persistent consistency point created by creating a partial consistency point for one or more of the first pointers and second pointers to selected blocks of data;

a status indicator set to indicate that an identified partial consistency point is completed; and

an operating system to coalesce all partial consistency points into a final completed consistency point for the selected time after all of the partial consistency points reach a status of completed.

17. The storage system of claim 16, further comprising:

the operating system to save the final completed consistency point in persistent storage on a computer system holding data stored in the storage system.

18. The storage system of claim 16, further comprising:

a network adapter to transfer data of the final completed consistency point over a computer network to a target computer; and

an operating system of the target computer to write the final completed consistency point in persistent storage.

19. The storage system of claim 16, further comprising:

the operating system to roll back a partial consistency point in response to a failure in transferring partial consistency point data to a persistent storage.

20. A storage system, comprising:

a root node having first pointers to a plurality of lower nodes, the lower nodes having reference through a plurality of second pointers to point to blocks of persistent storage, the blocks of persistent storage storing data of the storage system; and

an operating system to create a persistent consistency point of the storage system at a selected time, the persistent consistency point created by creating a partial consistency point for one or more of the first pointers and second pointers to selected blocks of data.

21. The storage system of claim 20, further comprising:

a status indicator to indicate that an identified partial consistency point is completed; and

the operating system to coalesce all partial consistency points into a final completed consistency point for the selected time after all of the partial consistency points reach a status of completed.

22. A computer readable media, comprising:

said computer readable media containing instructions for execution on a processor for the practice of a method of operating a storage system, the method having the steps of,

maintaining a root node having first pointers to a plurality of lower nodes, the lower nodes having reference through a plurality of second pointers to point to blocks of persistent storage, the blocks of persistent storage storing data of the storage system; and

creating a persistent consistency point of the storage system at a selected time, the persistent consistency point created by creating a partial consistency point for one or more of the first pointers and second pointers to selected blocks of data.

23. A method for operating a storage system, comprising:

maintaining a root node of a qtree comprising first pointers to a plurality of lower nodes, the lower nodes comprising a plurality of second pointers that point to blocks of persistent storage, the blocks of persistent storage storing data of the storage system;

creating a persistent consistency point of the storage system at a selected time, the persistent consistency point created by creating a partial consistency point for one or more of the first pointers and second pointers to selected blocks of data;

setting a status indicator to indicate that an identified partial consistency point is completed; and

coalescing all partial consistency points into a final completed consistency point for the selected time after all of the partial consistency points reach a completed status.

24. The method as in claim 23, further comprising:

saving the final completed consistency point in persistent storage by an operating system of a computer maintaining the storage system.

25. The method as in claim 23, further comprising:

transferring data of the final completed consistency point over a computer network to a target computer; and

saving the final completed consistency point in persistent storage by the target computer.

26. The method as in claim 23, further comprising:

rolling back a partial consistency point in response to a failure in transferring partial consistency point data to a persistent storage.

27. A method for operating a storage system, comprising:

maintaining a root node having one or more qtrees, the qtrees comprising one or more first pointers to a plurality of lower nodes, the lower nodes having reference through a plurality of second pointers to point to blocks of persistent storage, the blocks of persistent storage storing data of the storage system; and

creating a persistent consistency point of the storage system at a selected time, the persistent consistency point created by creating a partial consistency point for one or more of the qtrees to selected blocks of data.

28. The method of claim 27, further comprising:

setting a status indicator to indicate that an identified partial consistency point is completed; and

coalescing all partial consistency points into a final completed consistency point for the selected time after all of the partial consistency points reach a completed status.

29. A method for operating a storage system, comprising:

maintaining a root node having a qtree, the qtree comprising first pointers to a plurality of lower nodes, the lower nodes having reference through a plurality of second pointers to blocks of persistent storage storing data of the storage system;

identifying a sub-organization of the pointers;

creating a persistent consistency point of the storage system at a selected time, the persistent consistency point created by creating a partial consistency point for one or more of the sub-organizations of pointers;

setting a status indicator to indicate that an identified partial consistency point is completed; and

coalescing all partial consistency points into a final completed consistency point for the selected time after all of the partial consistency points reach a completed status.

30. A storage system, comprising:

a root node having a qtree, the qtree comprising first pointers to a plurality of lower nodes, the lower nodes having reference through a plurality of second pointers to point to blocks of persistent storage, the blocks of persistent storage storing data of the storage system;

a persistent consistency point of the storage system created at a selected time, the persistent consistency point created by creating a partial consistency point for one or more of the qtrees to selected blocks of data;

a status indicator set to indicate that an identified partial consistency point is completed; and

an operating system to coalesce all partial consistency points into a final completed consistency point for the selected time after all of the partial consistency points reach a completed status.

31. The storage system of claim 30, wherein the operating system is further configured to save the final completed consistency point in persistent storage on a computer system holding data stored in the storage system.

32. The storage system of claim 30, further comprising:

a network adapter adapted to transfer data of the final completed consistency point over a computer network to a target computer; and

an operating system of the target computer configured to write the final completed consistency point in persistent storage.

33. The storage system of claim 30, the operating system further configured to roll back a partial consistency point in response to a failure in transferring partial consistency point data to a persistent storage.

34. A storage system, comprising:

a root node having a qtree, the qtree comprising first pointers to a plurality of lower nodes, the lower nodes having reference through a plurality of second pointers to point to blocks of persistent storage, the blocks of persistent storage storing data of the storage system; and

an operating system to create a persistent consistency point of the storage system at a selected time, the persistent consistency point created by creating a partial consistency point for one or more of the first pointers and second pointers to selected blocks of data.

35. The storage system of claim 34, further comprising:

a status indicator to indicate that an identified partial consistency point is completed; and

the operating system to coalesce all partial consistency points into a final completed consistency point for the selected time after all of the partial consistency points reach a status of completed.

36. A computer readable media, comprising:

said computer readable media containing instructions for execution on a processor for the practice of a method of operating a storage system, the method comprising the steps of,

maintaining a root node having a qtree, the qtree comprising first pointers to a plurality of lower nodes, the lower nodes having reference through a plurality of second pointers to point to blocks of persistent storage, the blocks of persistent storage storing data of the storage system; and

creating a persistent consistency point of the storage system at a selected time, the persistent consistency point created by creating a partial consistency point for one or more of the first pointers and second pointers to selected blocks of data.