Method, system, and apparatus for releasing storage in a fast replication environment

• US 20040205311A1
• Filed: 04/08/2003
• Published: 10/14/2004
• Est. Priority Date: 04/08/2003
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Hulsey, John Allen
• Granted Patent: US 7,032,090 B2
• Time in Patent Office: Days
• US Class Current: 711/162
• CPC Class Codes: G06F 11/2069 Management of state, configuration or failover
• CPC Class Codes: G06F 11/2071 using a plurality of controllers
• CPC Class Codes: Y10S 707/99953 Recoverability
• CPC Class Codes: Y10S 707/99954 Version management

Abstract

Regions of data storage involved with fast replication relationships are managed and tracked in order to maintain the integrity of the data on the source and target volumes. In response to a delete operation referencing specified regions of storage, pending fast replication transfers are completed for source regions, fast replication relationships within the specified regions are withdrawn, and the specified regions of storage are release for subsequent allocation and reuse. The present invention facilitates maintaining synchronization of the storage management components of operating systems with the fast replication mechanisms of storage controllers, and releases unused storage regions for subsequent use. A storage subsystem may receive a delete command and make a determination of whether to release the specified regions of storage according to a state of a fast replication relationship with the regions of storage.

Claims

1. A method for managing fast replication-capable storage, the method comprising:

allocating regions of storage to provide allocated storage;

establishing a fast replication relationship for specified regions of the allocated storage; and

communicating a message to a storage server to release a specified region of allocated storage for future use, the message sufficient for the storage server to select an operation on the specified region of allocated storage according to a state of the fast replication relationship of the specified region of allocated storage.

2. The method of claim 1, wherein the operation comprises releasing the allocated storage for subsequent use.

3. The method of claim 1, wherein the operation is selected to comprise:

starting a background copy when the specified regions comprise the source of a fast replication operation and the specified region is not available for copying;

withdrawing the fast replication relationship when a copy completes when the specified regions comprise the source of a fast replication operation and the specified region is available for copying;

withdrawing a fast replication relationship when the specified regions comprise the target of the fast replication relationship; and

taking no action when the specified regions are not part of a fast replication relationship.

4. The method of claim 1, wherein communicating from a host to a storage server comprises issuing a dataset delete command to a storage subsystem.

5. The method of claim 1, wherein the communications comprise extents that identify a contiguous area of storage.

6. The method of claim 1, wherein the specified regions of storage comprise units selected from the group consisting of tracks, cylinders, sectors, and blocks.

7. A method for controlling storage devices, the method comprising:

receiving communication referencing specified regions involved in fast replication relationships to be released for subsequent use; and

selecting an operation to be conducted for the specified regions according to a state of a fast replication relationship with the specified regions.

8. The method of claim 7, wherein the operation is selected to comprise:

starting a background copy when the specified regions comprise the source of a fast replication operation and the specified region is not available for copying;

withdrawing the fast replication relationship when a copy completes when the specified regions comprise the source of a fast replication operation and the specified region is available for copying;

withdrawing a fast replication relationship when the specified regions comprise the target of the fast replication relationship; and

taking no action when the specified regions are not part of a fast replication relationship.

9. The method of claim 8, further comprising transferring data within the specified regions to a target device previous to withdrawing the fast replication relationship

10. The method of claim 7, further comprising informing a storage management module that the specified regions can be released for subsequent use.

11. The method of claim 7, further comprising tracking regions of storage involved in fast replication relationships.

12. The method of claim 11, wherein tracking regions of storage involved in a fast replication relationship and withdrawing the fast replication relationship comprises marking and unmarking regions of storage.

13. The method of claim 7, wherein the communication referencing the specified regions to be released for subsequent use is provided by a storage management module residing on a host.

14. The method of claim 7, wherein the communication referencing the specified regions comprises extents that identify a contiguous area of storage.

15. The method of claim 7, wherein the regions of storage comprise units selected from the group consisting of tracks, cylinders, sectors, and blocks.

16. An apparatus for controlling fast replication capable storage devices, the apparatus comprising:

a transfer module configured to transfer data stored within regions involved in a fast replication relationship to a target device; and

a tracking module configured to selectively withdraw the fast replication relationship for specified regions upon receipt of a message from a storage server to release allocated storage for future use, and based upon a determination of a state of a fast replication relationship with the specified regions of the allocated storage.

17. The apparatus of claim 16, wherein the tracking module is further configured to inform a storage management module that the specified regions can be released for subsequent use.

18. The apparatus of claim 16, wherein the tracking module is further configured to initiate a transfer of data stored within the specified regions to a target device.

19. The apparatus of claim 16, wherein the tracking module resides on a storage controller.

20. The apparatus of claim 16, wherein the regions comprise units selected from the group consisting of tracks, cylinders, sectors, and blocks.

21. The apparatus of claim 16, wherein the tracking module is further configured to withdraw the fast replication relationship for the specified regions in response to a delete operation referencing the specified regions.

22. An apparatus for controlling fast replication capable storage devices, the apparatus comprising:

means for transferring data stored within regions involved in a fast replication relationship to a target device; and

means for selectively withdrawing the fast replication relationship for specified regions upon receipt of a message from a storage server to release allocated storage for future use, and based upon a determination of a state of a fast replication relationship with the specified regions of the allocated storage.

23. The apparatus of claim 22, further comprising means for transferring data stored within regions involved in a fast replication relationship to a target device.

24. A system for managing storage involved in a fast replication relationship, the system comprising:

a host comprising a storage management module configured to allocate storage and initiate establishment and withdrawal of fast replication relationships;

a storage subsystem configured to control storage devices and complete establishment and withdrawal of fast replication relationships for specified regions of storage upon receipt of a delete message from the host, the storage management module further configured to selectively withdraw the fast replication relationship for specified regions upon receipt of a message from a storage server to release allocated storage for future use, and based upon a determination of a state of a fast replication relationship with the specified regions of the allocated storage.

25. A computer readable storage medium comprising computer readable program code means for managing storage involved in a fast replication relationship, the program code means configured to:

track regions of storage involved in a fast replication relationship; and

selectively withdraw the fast replication relationship for specified regions upon receipt of a message from a storage server to release allocated storage for future use, and based upon a determination of a state of a fast replication relationship with the specified regions of the allocated storage.

26. A method for controlling storage devices, the method comprising:

receiving communication referencing specified regions involved in fast replication relationships to be released for subsequent use;

selecting an operation to be conducted for the specified regions according to a state of a fast replication relationship with the specified regions;

starting a background copy when the specified regions comprise the source of a fast replication operation and the specified region is not available for copying;

withdrawing the fast replication relationship when a copy completes when the specified regions comprise the source of a fast replication operation and the specified region is available for copying;

withdrawing a fast replication relationship when the specified regions comprise the target of the fast replication relationship; and

taking no action when the specified regions are not part of a fast replication relationship.