Updating metadata in a logical volume associated with a storage controller for data units indicated in a data structure

• US 8,140,785 B2
• Filed: 06/29/2006
• Issued: 03/20/2012
• Est. Priority Date: 06/29/2006
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Kalos, Matthew J., Kubo, Robert Akira
• Primary Examiner(s): Ellis, Kevin L
• Assistant Examiner(s): DAVIDSON, CHAD
• Application Number:
  US11/427,743
• Publication Number:
  US 20080005146A1
• Time in Patent Office: 2,091 Days
• Field of Search: 711/161
• US Class Current: 711/161
• CPC Class Codes: G06F 3/061 Improving I/O performance
• CPC Class Codes: G06F 3/0643 Management of files
• CPC Class Codes: G06F 3/0647 Migration mechanisms
• CPC Class Codes: G06F 3/067 Distributed or networked storage systems, e.g. storage area networks [SAN], network attached storage [NAS]

Abstract

Provided are a method, system, and article of manufacture for updating metadata in a logical volume associated with a storage controller. A data structure is generated indicating data units in a volume whose metadata is to be updated. An operation is initiated to update the metadata for data units indicated in the data structure. Indication is made in the data structure that the metadata for one data unit has been updated in response to updating the metadata for the data unit. An Input/Output (I/O) request is received to one data unit in the volume while the metadata for the data units indicated in the data structure is being updated. A determination is made, in response to the I/O request, from the data structure whether the metadata for the requested data unit was updated. The metadata for the requested data unit is updated in response to determining that the metadata for the requested data unit has not been updated. The I/O request is executed against the requested data unit.

Claims

1. A method, comprising:

generating a data structure indicating data units in a volume whose metadata is to be updated;

initiating an operation to update the metadata for the data units indicated in the data structure, wherein updating the metadata comprises modifying a field in the metadata for the data units indicated in the data structure;

indicating in the data structure that the metadata for one of the data units has been updated in response to updating the metadata for the data unit;

receiving an Input/Output (I/O) request to one of the data units in the volume while the metadata for the data units indicated in the data structure is being updated;

determining, in response to the I/O request, from the data structure whether the metadata for the requested data unit was updated;

updating the metadata for the requested data unit in response to determining that the metadata for the requested data unit has not been updated; and

executing the I/O request against the requested data unit.

2. The method of claim 1, wherein the I/O request is executed against the requested data unit in response to updating the metadata for the requested data unit or determining that the data structure indicates that the metadata for the requested data unit has been updated.

3. The method of claim 1, wherein the volume including the data units indicated in the data structure is in a storage device configured for use with a first storage server, further comprising:

associating the volume in the storage device with a second storage server for use with the second storage server.

4. The method of claim 3, wherein associating the volume with the second storage server, comprises:

determining a volume number to assign to the volume for use with the second storage server, wherein the metadata is updated to indicate the determined volume number for the volume.

5. The method of claim 1, wherein the data structure comprises a point-in-time copy relationship indicating the data units in the volume whose metadata is to be updated, wherein the point-in-time copy operation updates the metadata for the indicated data units without copying the data units.

6. The method of claim 5, further comprising:

configuring the copy relationship to have a source and target volumes point to a same physical location, wherein the data units indicated in the copy relationship as not copied from the source volume to the target volume have not had their metadata updated and wherein the data units indicated as copied from the source volume to the target volume have had their metadata updated.

7. The method of claim 1, wherein the I/O request comprises a write request, wherein the metadata is updated before applying the write request in response to determining that the metadata for the requested data unit has not been updated.

8. The method of claim 1, wherein modifying the metadata for the data units indicated in the data structure comprises updating a volume identifier (ID) in the metadata for the data units to indicate a new volume ID for the data units.

9. The method of claim 1, further comprising:

initiating operations to configure a storage device including the data units in the volume previously included in a first storage used by a first storage controller for use in a second storage used by a second storage controller, wherein the field in the metadata for the data units indicates a first volume identifier used to identify the volume to the first storage controller; and

determining a second volume identifier assigned by the second storage controller to the volume identified by the first volume identifier in the storage device included in the second storage, wherein updating the field in the metadata for the requested data unit comprises indicating in the field that the volume of the requested data unit is identified by the second volume identifier.

10. The method of claim 1, wherein the I/O request comprises a read request, wherein the metadata is updated before returning the requested data unit in response to determining that the metadata for the requested data unit has not been updated.

11. A system, comprising:

a computer readable storage medium including a data structure indicating data units in a volume whose metadata is to be updated; and

an Input/Output (I/O) manager executed to perform operations, the operations comprising;

generating the data structure indicating the data units in the volume whose metadata is to be updated;

initiating an operation to update the metadata for the data units indicated in the data structure, wherein updating the metadata comprises modifying a field in the metadata for the data units indicated in the data structure;

indicating in the data structure that the metadata for one of the data units has been updated in response to updating the metadata for the data unit;

receiving an Input/Output (I/O) request to one of the data units in the volume while the metadata for the data units indicated in the data structure is being updated;

determining, in response to the I/O request, from the data structure whether the metadata for the requested data unit was updated;

updating the metadata for the requested data unit in response to determining that the metadata for the requested data unit has not been updated; and

executing the I/O request against the requested data unit.

12. The system of claim 11, wherein the data structure comprises a point-in-time copy relationship indicating the data units in the volume whose metadata is to be updated, wherein the point-in-time copy operation updates the metadata for the indicated data units without copying the data units.

13. The system of claim 12, wherein the operations further comprise:

configuring the copy relationship to have a source and target volumes point to a same physical location, wherein the data units indicated in the copy relationship as not copied from the source volume to the target volume have not had their metadata updated and wherein the data units indicated as copied from the source volume to the target volume have had their metadata updated.

14. The system of claim 11, wherein the I/O request comprises a write request, wherein the metadata is updated before applying the write request in response to determining that the metadata for the requested data unit has not been updated.

15. The system of claim 11, wherein modifying the metadata for the data units indicated in the data structure comprises updating a volume identifier (ID) in the metadata for the data units to indicate a new volume ID for the data units.

16. The system of claim 11, wherein the volume is included in a storage device previously included in a first storage used by a first storage controller, further comprising:

a second storage controller;

a second storage used by the second storage controller including the I/O manager, wherein the operations performed by the I/O manager further comprise;

initiating operations to configure the storage device including the data units in the volume for use in the second storage, wherein the field in the metadata for the data units indicates a first volume identifier used to identify the volume to the first storage controller; and

determining a second volume identifier assigned by the second storage controller to the volume identified by the first volume identifier in the storage device included in the second storage, wherein updating the field in the metadata for the requested data unit comprises indicating in the field that the volume of the requested data unit is identified by the second volume identifier.

17. The system of claim 11, wherein the I/O request comprises a read request, wherein the metadata is updated before returning the requested data unit in response to determining that the metadata for the requested data unit has not been updated.

18. The system of claim 11, wherein the I/O request is executed against the requested data unit in response to updating the metadata for the requested data unit or determining that the data structure indicates that the metadata for the requested data unit has been updated.

19. An article of manufacture comprising a computer readable storage medium including code executed by a processor to perform operations, the operations comprising:

generating a data structure indicating data units in a volume whose metadata is to be updated;

initiating an operation to update the metadata for the data units indicated in the data structure, wherein updating the metadata comprises modifying a field in the metadata for the data units indicated in the data structure;

indicating in the data structure that the metadata for one of the data units has been updated in response to updating the metadata for the data unit;

receiving an Input/Output (I/O) request to one of the data units in the volume while the metadata for the data units indicated in the data structure is being updated;

determining, in response to the I/O request, from the data structure whether the metadata for the requested data unit was updated;

updating the metadata for the requested data unit in response to determining that the metadata for the requested data unit has not been updated; and

executing the I/O request against the requested data unit.

20. The article of manufacture of claim 19, wherein the data structure comprises a point-in-time copy relationship indicating the data units in the volume whose metadata is to be updated, wherein the point-in-time copy operation updates the metadata for the indicated data units without copying the data units.

21. The article of manufacture of claim 20, wherein the operations further comprise:

configuring the copy relationship to have a source and target volumes point to a same physical location, wherein the data units indicated in the copy relationship as not copied from the source volume to the target volume have not had their metadata updated and wherein the data units indicated as copied from the source volume to the target volume have had their metadata updated.

22. The article of manufacture of claim 19, wherein the I/O request comprises a write request, wherein the metadata is updated before applying the write request in response to determining that the metadata for the requested data unit has not been updated.

23. The article of manufacture of claim 19, wherein modifying the metadata for the data units indicated in the data structure comprises updating a volume identifier (ID) in the metadata for the data units to indicate a new volume ID for the data units.

24. The article of manufacture of claim 19, wherein the volume is included in a storage device previously included in a first storage used by a first storage controller, and wherein the computer readable storage medium is included in a second storage controller using a second storage, wherein the operations further comprise:

initiating operations to configure the storage device including the data units in the volume for use in the second storage, wherein the field in the metadata for the data units indicates a first volume identifier used to identify the volume to the first storage controller; and

determining a second volume identifier assigned by the second storage controller to the volume identified by the first volume identifier in the storage device included in the second storage, wherein updating the field in the metadata for the requested data unit comprises indicating in the field that the volume of the requested data unit is identified by the second volume identifier.

25. The article of manufacture of claim 19, wherein the I/O request comprises a read request, wherein the metadata is updated before returning the requested data unit in response to determining that the metadata for the requested data unit has not been updated.

26. The article of manufacture of claim 19, wherein the I/O request is executed against the requested data unit in response to updating the metadata for the requested data unit or determining that the data structure indicates that the metadata for the requested data unit has been updated.