Disaster recovery

• US 20040078397A1
• Filed: 10/22/2002
• Published: 04/22/2004
• Est. Priority Date: 10/22/2002
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: NuView, Inc. (Broadcom, Inc.)
• Inventors: Van Horn, Steve, Mehta, Rahul, Glitsch, Hans, Place, Paul
• Granted Patent: US 7,814,050 B2
• Time in Patent Office: Days
• US Class Current: 707/202
• CPC Class Codes: G06F 11/1451 by selection of backup contents
• CPC Class Codes: G06F 11/1464 for networked environments
• CPC Class Codes: G06F 11/1469 Backup restoration techniques
• CPC Class Codes: G06F 11/1662 the resynchronized component or unit being a persistent storage device re-synchronization of failed mirror storage G06F11/2082; rebuild or reconstruction of parity RAID storage G06F11/1008
• CPC Class Codes: G06F 11/2094 Redundant storage or storage space G06F11/2056 takes precedence
• CPC Class Codes: G06F 11/2097 maintaining the standby controller/processing unit updated initialisation or re-synchronisation thereof G06F11/1658 and subgroups

Abstract

File system disaster recovery techniques provide automated monitoring, failure detection and multi-step failover from a primary designated target to one of a designated group of secondary designated targets. Secondary designated targets may be prioritized so that failover occurs in a prescribed sequence. Replication of information between the primary designated target and the secondary designated targets allows failover in a manner that maximizes continuity of operation. In addition, user-specified actions may be initiated on failure detection and/or on failover operations and/or on failback operations.

Claims

1. A logical namespace disaster recovery method, comprising:

monitoring one or more designated resources;

detecting a failed resource from the one or more designated resources;

identifying a designated alternate resource associated with the failed resource; and

swapping the designated alternate resource for the failed resource.

2. The method of claim 1, wherein the act of monitoring comprises:

issuing a command to a designated resource; and

waiting for an appropriate response from the designated resource in response to the issued command.

3. The method of claim 2, wherein the act of issuing a command comprises issuing a directory listing command.

4. The method of claim 1, wherein the act of monitoring further comprises periodically replicating data associated with a designated resource to a second storage location.

5. The method of claim 4, wherein the act of replicating data to a second storage location comprises replicating data to a location identified by a designated alternate resource associated with the designated resource.

6. The method of claim 1, wherein the act of monitoring further comprises periodically replicating data associated with one of the one or more designated resources to one or more alternate storage locations.

7. The method of claim 6, wherein the act of replicating data to one or more alternate storage locations comprises replicating data to storage locations identified by the one or more designated alternate resources associated with the one of the one or more designated resources.

8. The method of claim 2, wherein the act of detecting comprises determining that an appropriate reply to the issued command was not received.

9. The method of claim 8, wherein the act of determining that an appropriate response to the issued command was not received comprises, not receiving a reply responsive to the issued command within a specified time period.

10. The method of claim 1, wherein the act of identifying comprises:

identifying a plurality of designated alternate resources associated with the failed resource; and

selecting one of the plurality of designated alternate resources.

11. The method of claim 10, wherein the act of selecting one of the plurality of designated alternate resources comprises selecting one of the plurality of designated alternate resources in accordance with a specified priority scheme.

12. The method of claim 11, wherein the act of selecting in accordance with a specified priority scheme comprises selecting in accordance with a user-specified priority scheme.

13. The method of claim 12, wherein the act of selecting in accordance with a user-specified priority scheme comprises selecting that designated alternate resource having the most recent replicate of data associated with the failed resource.

14. The method of claim 1, wherein the act of swapping comprises substituting the identified designated alternate resource for the failed resource so that a message directed to the failed resource is sent to the identified designated alternate resource in a manner transparent to a user issuing the command.

15. The method of claim 1, further comprising invoking a user-specified action after the act of detecting and before the act of swapping.

16. The method of claim 15, wherein the act of invoking a user-specified action comprises invoking a routine to record the detected resource failure in a log.

17. The method of claim 1, further comprising invoking a user-specified action after the act of swapping.

18. The method of claim 17, wherein the act of invoking a user-specified action comprises invoking a routine to record the act of swapping the designated alternate resource for the failed resource.

19. The method of claim 1, wherein the logical namespace disaster recovery method comprises a distributed file system (DFS) disaster recovery method.

20. The method of claim 19, wherein the one or more designated resources comprise one or more designated shared directories.

21. The method of claim 20, wherein a designated alternate resource comprises a shared directory.

22. The method of claim 21, wherein the act of identifying comprises identifying a link replica associated with the failed resource.

23. A program storage device, readable by a programmable control device, comprising instructions stored on the program storage device for causing the programmable control device to

monitor one or more designated resources;

detect a failed resource from the one or more designated resources;

identify a designated alternate resource associated with the failed resource; and

swap the designated alternate resource for the failed resource.

24. The program storage device of claim 23, wherein the instructions to monitor comprise instructions to:

issue a command to a designated resource; and

wait for an appropriate response from the designated resource in response to the issued command.

25. The program storage device of claim 24, wherein the instruction to issue a command comprises an instruction to issue a directory listing command.

26. The program storage device of claim 23, wherein the instructions to monitor further comprise instructions to periodically replicate data associated with a designated resource to a second storage location.

27. The program storage device of claim 26, wherein the instructions to periodically replicate data to a second storage location comprise instructions to replicate data to a location identified by a designated alternate resource associated with the designated resource.

28. The program storage device of claim 24, wherein the instructions to detect comprise instructions to determine that an appropriate reply to the issued command was not received.

29. The program storage device of claim 23, wherein the instructions to identify comprise instructions to:

identify a plurality of designated alternate resources associated with the failed resource; and

select one of the plurality of designated alternate resources.

30. The program storage device of claim 29, wherein the instructions to select one of the plurality of designated alternate resources comprise instructions to select one of the plurality of designated alternate resources in accordance with a specified priority scheme.

31. The program storage device of claim 23, wherein the instructions to swap comprise instructions to substitute the identified designated alternate resource for the failed resource so that a message directed to the failed resource is sent to the identified designated alternate resource in a manner transparent to a user issuing the command.

32. The program storage device of claim 23, further comprising instructions to invoke a user-specified action after the instructions to detect and before the instructions to swap.

33. The program storage device of claim 23, further comprising instructions to invoke a user-specified action after the instructions to swap.

34. A disaster recovery system, comprising:

a plurality of logical resources, each logical resource associated with a physical resource;

logical namespace means for routing requests directed to a designated logical resource to an associated physical resource, said logical namespace means operatively coupled to each of the logical resources;

monitor means for actively monitoring one or more of the physical resources; and

recovery means for receiving notification from the monitor means that a physical resource has failed and causing the logical namespace means to substitute a designated alternate physical resource for the failed physical resource.

35. The disaster recovery system of claim 34, wherein the physical resources comprise directory structures in a computer network, at least one of the physical resources being designated as a primary physical resource and at least another one of the physical resources being designated as a secondary physical resource for the primary physical resource.

36. The disaster recovery system of claim 35, wherein the logical namespace means comprises a distributed file system (DFS) logical namespace.

37. The disaster recovery system of claim 36, wherein the logical namespace means identifies a secondary physical resource through a DFS link-replica means.

38. The disaster recovery system of claim 37, wherein a designated primary physical resource is associated with a plurality of secondary physical resources.

39. The disaster recovery system of claim 34, wherein the monitor means comprises a means for issuing periodic queries to at least one of the physical resources to determine if the logical resource is operational.

40. The disaster recovery system of claim 39, wherein the means for issuing periodic queries comprises issuing directory listing queries.

41. The disaster recovery system of claim 36, wherein the recovery means for causing the logical namespace means to substitute a designated alternate physical resource for the failed physical resource comprises using DFS application programming interface (API) commands to:

remove the failed physical resource from active use in the DFS; and

using a designated alternate physical resource for the failed physical resource in the DFS.

42. The disaster recovery system of claim 41, wherein the recovery means uses one designated alternate physical resource from a plurality of alternate physical resources associated with the failed physical resource.

43. The disaster recovery system of claim 42, wherein the recovery means selects the one designated alternate physical resource from the plurality of alternate physical resources in accordance with a priority scheme.

44. The disaster recovery system of claim 43, wherein the recovery means selects the one designated alternate physical resource in accordance with a user-specified priority scheme.

45. The disaster recovery system of claim 34, further comprising an execution means for executing a user-specified action after the monitor means detects failure of a physical resource.

46. The disaster recovery system of claim 45, further comprising a second execution means for executing a second user-specified action after the recovery means causes the logical namespace means to substitute a designated alternate physical resource for the failed physical resource.

47. The disaster recovery system of claim 34, further comprising a replication means for replicating information associated with a first physical resource to a second physical resource.

48. The disaster recovery system of claim 47, wherein the replication means replicates information associated with the first physical resource to a plurality of secondary physical resources.

49. The disaster recovery system of claim 34, wherein the monitor means comprises a first computer executable module executing on a first computer system and the recovery means comprises a second computer executable module executing on a second, different, computer system.

50. The disaster recovery system of claim 34, wherein the logical namespace means and the disaster recovery means comprise separate computer executable modules executing on a common computer system.