System and method for storage takeover

• US 7,930,587 B1
• Filed: 08/27/2009
• Issued: 04/19/2011
• Est. Priority Date: 11/30/2006
• Status: Active Grant

• Current Assignee: NetApp, Inc.
• Original Assignee: NetApp, Inc.
• Inventors: Coatney, Susan M., Watanabe, Steven S., Strange, Stephen H., Patel, Kayuri
• Primary Examiner(s): Bonzo; Bryce P
• Application Number:
  US12/548,501
• Time in Patent Office: 600 Days
• Field of Search: 714/7
• US Class Current: 714/6.32
• 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 11/0757 by exceeding a time limit, i.e. time-out, e.g. watchdogs
• CPC Class Codes: G06F 11/2033 switching over of hardware resources
• CPC Class Codes: G06F 11/2046 where the redundant components share persistent storage G06F11/2043 takes precedence

Abstract

A system and method for performing a takeover procedure is disclosed. A plurality of storage system nodes is coupled in a cluster. One or more of the plurality of storage system nodes in the cluster is notified to takeover at least a portion of a writable storage device serviced by another storage system node in the cluster. In response to the notification, the portion of the writable storage device is assimilated into at least one of the notified storage system nodes.

Claims

1. A method for performing a takeover procedure, comprising:

coupling a plurality of storage system nodes in a cluster;

triggering a takeover process for a first storage system node of the plurality of storage system nodes in the cluster to takeover a portion of a writable storage device serviced by a second storage system node of the plurality of storage system nodes in the cluster;

in response to triggering the takeover process, assimilating the portion of the writable storage device into one or more data containers serviced by the first storage system node;

checking whether the assimilated portion comprises a first volume identification (ID) that matches a second volume ID of the first storage system node; and

in response to a match, assigning a new volume ID to the first volume ID or assigning the new volume ID to the second volume ID.

2. The method of claim 1 wherein the portion of the writable storage device is assimilated by a RAID system process of the first storage system node.

3. The method of claim 1 further comprising asserting, by the first storage system node, ownership of the portion of the writable storage device serviced by the second storage system node.

4. The method of claim 3 wherein asserting ownership comprises using a fencing technique.

5. The method of claim 1 further comprising:

assigning a status in an ownership locations associated with the portion of the writable storage device; and

identifying the first storage system node as a current owners of the portion of the writable storage device by the assigned status.

6. The method of claim 5 wherein the ownership location is on the writable storage device.

7. The method of claim 1 wherein the first volume ID comprises a file system ID.

8. The method of claim 1 further comprising:

storing memory data from the second storage system node to a memory of the first storage system node; and

replaying the stored memory data from the memory of the first storage system node.

9. The method of claim 1 further comprising appearing to the first storage system node that the assimilated portion of the writable storage device is local to the first storage system node.

10. The method of claim 1 further comprising updating a volume location database to reflect the assimilation.

11. The method of claim 1 wherein the first storage system node comprises a network element.

12. The method of claim 1 wherein the first storage system node comprises a D-module and a network element.

13. The method of claim 1 wherein the portion of the writable storage device is assimilated into an aggregate of the first storage system node.

14. The method of claim 1 further comprising:

pre-empting a second storage system node reservation on the portion of the writable storage device; and

asserting a first storage system node reservation on the portion of the writable storage device.

15. The method of claim 14 wherein the first storage system node reservation comprises a small computer systems interface (SCSI) reservation.

16. The method of claim 1 wherein the writable storage device comprises electronic random access memory.

17. A computer system for use in a clustered environment, comprising:

a first storage system node configured to operatively connect with a second storage system node;

the first storage system node further configured to provide a communication path between the first storage system node and the second storage system node; and

a processor operatively interconnected with the first storage system node and configured to execute a takeover procedure, the takeover procedure configured to assimilate a portion of a writable storage device serviced by the second storage system node into one or more data containers serviced by the first storage system node, the takeover procedure further configured to check whether the assimilated portion comprises a first volume identification (ID) that matches a second volume ID of the first storage system node, and in response to a match, assign a new volume ID to the first volume ID or assign the new volume ID to the second volume ID.

18. The computer system of claim 17 wherein the first volume ID comprises a file system ID.

19. The computer system of claim 17 wherein the takeover procedure is further configured to instruct an ownership module of the first storage system node to change one or more ownership attributes of the writable storage device from the second storage system node to the first storage system node.

20. The computer system of claim 17 wherein the first storage system node is further configured to assert ownership on the portion of the writable storage device serviced by the second storage system node.

21. The computer system of claim 17 wherein the writable storage device is electronic random access memory.

22. The computer system of claim 17 wherein the one or more data containers comprises an aggregate.

25. The computer system of claim 17, wherein the takeover procedure is further configured to pre-empt a reservation of the second storage system node on the portion of the writable storage device.

26. The computer-readable medium of claim 25, further comprising program instructions that preempt a second storage system node reservation on the portion of the writable storage device and program instructions that assert a first storage system node reservation on the portion of the writable storage device.

27. The computer system of claim 17 wherein the takeover procedure is further configured to store memory data from the second storage system node to a memory of the first storage system node, and further configured to replay the stored memory data from the memory of the first storage system node.

28. The computer system of claim 17 wherein the assimilation is performed by a RAID system process of the first storage system node.

23. A computer-readable storage medium containing executable program instructions executed by a processor, comprising:

program instructions that trigger a takeover process for a first storage system node of a plurality of storage system nodes in a cluster to takeover a portion of a writable storage device serviced by a second storage system node in the cluster;

program instructions that, in response to triggering the takeover process, assimilate the portion of the writable storage device into one or more data containers serviced by the first storage system node;

program instructions that check whether the assimilated portion comprises a first volume identification (ID) that matches a second volume ID of the first storage system node; and

program instructions that, in response to a match, assign a new volume ID to the first volume ID or that assign the new volume ID to the second volume ID.

24. The computer-readable medium of claim 23, further comprising program instructions that change one or more ownership attributes of the portion of the writable storage device from the second storage system node to the first storage system node.

29. The computer-readable medium of claim 23 wherein the writable storage device is an electronic random access memory.

30. The computer-readable medium of claim 23 wherein the one or more data containers comprises an aggregate.