RELOCATING A LOGICAL VOLUME FROM A FIRST STORAGE LOCATION TO A SECOND STORAGE LOCATION USING A COPY RELATIONSHIP

• US 20080052478A1
• Filed: 06/29/2006
• Published: 02/28/2008
• Est. Priority Date: 06/29/2006
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Kubo, Robert Akira, Kalos, Matthew Joseph
• Granted Patent: US 7,930,496 B2
• Time in Patent Office: Days
• US Class Current: 711/162
• CPC Class Codes: G06F 3/0605 by facilitating the interaction with a user or administrator
• CPC Class Codes: G06F 3/0647 Migration mechanisms
• CPC Class Codes: G06F 3/0689 Disk arrays, e.g. RAID, JBOD

Abstract

Provided are a method, system, and article of manufacture for relocating a logical volume from a first storage location to a second storage location using a copy relationship. An operation is initiated to move a logical volume from a first storage location to a second storage location. A relationship is established between the first and second storage locations to copy data in the logical volume from the first storage location to the second storage location. A read request is received to data in the logical volume while copying the data in the logical volume from the first storage location to the second storage location. A determination is made, in response to the read request, whether the requested data is at a first copy of the logical volume in the first storage location or a second copy of the logical volume as the second storage location. The requested data is returned from the determined first or second copy of the logical volume while the logical volume is being copied from the first storage location to the second storage location.

Claims

1. A method, comprising:

initiating an operation to move a logical volume from a first storage location to a second storage location;

establishing a relationship between the first and second storage locations to copy data in the logical volume from the first storage location to the second storage location;

receiving a read request to data in the logical volume while copying the data in the logical volume from the first storage location to the second storage location;

determining, in response to the read request, whether the requested data is at a first copy of the logical volume in the first storage location or a second copy of the logical volume at the second storage location; and

returning the requested data from the determined first or second copy of the logical volume while the logical volume is being copied from the first storage location to the second storage location.

2. The method of claim 1, further comprising:

receiving a request to write data to the logical volume while copying the data in the logical volume from the first copy to the second copy; and

writing the write data to the second copy of the logical volume at the second storage location.

3. The method of claim 2, wherein the logical volume comprises data units, wherein the relationship indicates for data units in the logical volume whether the data unit in the first copy of the logical volume was copied to the second copy of the logical volume, further comprising:

indicating that one data unit has been copied from the first copy of the logical volume to the second copy of the logical volume in response to writing the data to the second copy of the logical volume.

4. The method of claim 1, wherein the logical volume comprises data units, wherein the relationship indicates for each data unit in the logical volume whether the data unit in the first copy of the logical volume was copied to the second copy of the logical volume, and wherein determining whether the requested data is maintained at the first or second copy of the logical volume comprises:

determining whether the relationship indicates that the data unit including the requested data was copied from the first copy of the logical volume to the second copy of the logical volume, wherein the requested data is determined to be at the first copy in response to determining that the relationship indicates that the data unit including the requested data was not copied from the first copy to the second copy and wherein the requested data is determined to be at the second copy in response to determining that the relationship indicates that the data unit including the requested data was copied from the first copy to the second copy.

5. The method of claim 1, further comprising:

freeing the space used by a data unit copied from the first copy of the logical volume to the second copy of the logical volume in response to completing the copying of the data unit to the second copy of the logical volume and before all the data units for the logical volume are copied to the second copy of the logical volume.

6. The method of claim 1, further comprising:

freeing the space used by data units in the first copy of the logical volume in response to completing the copying of all the data units from the first copy of the logical volume to the second copy of the logical volume.

7. The method of claim 1, further comprising:

mapping read request to addresses of the logical volume to the determined first or second copy of the logical volume while the relationship indicates that data in the logical volume is being copied from the first storage location to the second storage location; and

mapping read requests to addresses of the logical volume to the second copy of the logical volume at the second storage location in response to completing the copying of the first copy of the logical volume to the second copy.

8. The method of claim 1, wherein the relationship to copy data in the logical volume from the first storage location to the second storage location comprises a point-in-time copy relationship.

9. The method of claim 1, further comprising:

initiating an operation to copy data units of the first copy of the logical volume to corresponding data units of the second copy of the logical volume in response to establishing the copy relationship; and

indicating that one data unit has been copied in response to copying the first copy of the logical volume to the second copy of the logical volume, wherein one data unit is determined to be at the first copy of the logical volume if the data unit is indicated as not copied to the second copy of the logical volume, and wherein one data unit is determined to be at the second copy of the logical volume if the data unit is indicated as having been copied to the second copy of the logical volume.

10. A system in communication with a first and second storage locations, comprising:

a processor; and

a program executed by the processor to perform operations, the operations comprising;

receiving a request to move a logical volume from a first storage location to a second storage location;

establishing a relationship between the first and second storage locations to copy data in the logical volume from the first storage location to the second storage location;

receiving a read request to data in the logical volume while copying the data in the logical volume from the first storage location to the second storage location;

determining, in response to the read request, whether the requested data is at a first copy of the logical volume in the first storage location or a second copy of the logical volume at the second storage location; and

returning the requested data from the determined first or second copy of the logical volume while the logical volume is being copied from the first storage location to the second storage location.

11. The system of claim 10, wherein the operations further comprise:

receiving a request to write data to the logical volume while copying the data in the logical volume from the first copy to the second copy; and

writing the write data to the second copy of the logical volume at the second storage location.

12. The system of claim 11, wherein the logical volume comprises data units, wherein the relationship indicates for each data unit in the logical volume whether the data unit in the first copy of the logical volume was copied to the second copy of the logical volume, wherein the operations further comprise:

indicating that one data unit has been copied from the first copy of the logical volume to the second copy of the logical volume in response to writing the data to the second copy of the logical volume.

13. The system of claim 10, wherein the logical volume comprises data units, wherein the relationship indicates for each data unit in the logical volume whether the data unit in the first copy of the logical volume was copied to the second copy of the logical volume, and wherein determining whether the requested data is maintained at the first or second copy of the logical volume comprises:

determining whether the relationship indicates that the data unit including the requested data was copied from the first copy of the logical volume to the second copy of the logical volume, wherein the requested data is determined to be at the first copy in response to determining that the relationship indicates that the data unit including the requested data was not copied from the first copy to the second copy and wherein the requested data is determined to be at the second copy in response to determining that the relationship indicates that the data unit including the requested data was copied from the first copy to the second copy.

14. The system of claim 10, wherein the operations further comprise:

mapping read requests to addresses of the logical volume to the determined first or second copy of the logical volume while the relationship indicates that data in the logical volume is being copied from the first storage location to the second storage location; and

mapping read requests to addresses of the logical volume to the second copy of the logical volume at the second storage location in response to completing the copying of the first copy of the logical volume to the second copy.

15. The system of claim 10, wherein the operations further comprise:

initiating an operation to copy data units of the first copy of the logical volume to corresponding data units of the second copy of the logical volume in response to establishing the copy relationship; and

indicating that one data unit has been copied in response to copying the first copy of the logical volume to the second copy of the logical volume, wherein one data unit is determined to be at the first copy of the logical volume if the data unit is indicated as not copied to the second copy of the logical volume, and wherein one data unit is determined to be at the second copy of the logical volume if the data unit is indicated as having been copied to the second copy of the logical volume.

16. An article of manufacture implementing code executed to perform operations with respect to a first and second storage locations and to perform further operations comprising:

initiating an operation to move a logical volume from a first storage location to a second storage location;

establishing a relationship between the first and second storage locations to copy data in the logical volume from the first storage location to the second storage location;

receiving a read request to data in the logical volume while copying the data in the logical volume from the first storage location to the second storage location;

determining, in response to the read request, whether the requested data is at a first copy of the logical volume in the first storage location or a second copy of the logical volume at the second storage location; and

returning the requested data from the determined first or second copy of the logical volume while the logical volume is being copied from the first storage location to the second storage location.

17. The article of manufacture of claim 16, wherein the operations further comprise:

receiving a request to write data to the logical volume while copying the data in the logical volume from the first copy to the second copy; and

writing the write data to the second copy of the logical volume at the second storage location.

18. The article of manufacture of claim 17, wherein the logical volume comprises data units, wherein the relationship indicates for data units in the logical volume whether the data unit in the first copy of the logical volume was copied to the second copy of the logical volume, wherein the operations further comprise:

indicating that one data unit has been copied from the first copy of the logical volume to the second copy of the logical volume in response to writing the data to the second copy of the logical volume.

19. The article of manufacture of claim 16, wherein the logical volume comprises data units, wherein the relationship indicates for each data unit in the logical volume whether the data unit in the first copy of the logical volume was copied to the second copy of the logical volume, and wherein determining whether the requested data is maintained at the first or second copy of the logical volume comprises:

determining whether the relationship indicates that the data unit including the requested data was copied from the first copy of the logical volume to the second copy of the logical volume, wherein the requested data is determined to be at the first copy in response to determining that the relationship indicates that the data unit including the requested data was not copied from the first copy to the second copy and wherein the requested data is determined to be at the second copy in response to determining that the relationship indicates that the data unit including the requested data was copied from the first copy to the second copy.

20. The article of manufacture of claim 16, wherein the operations further comprise:

mapping read requests to addresses of the logical volume to the determined first or second copy of the logical volume while the relationship indicates that data in the logical volume is being copied from the first storage location to the second storage location; and

mapping read requests to addresses of the logical volume to the second copy of the logical volume at the second storage location in response to completing the copying of the list copy of the logical volume to the second copy.

21. The article of manufacture of claim 16, wherein the operations further comprise:

initiating an operation to copy data units of the first copy of the logical volume to corresponding data units of the second copy of the logical volume in response to establishing the copy relationship; and

indicating that one data unit has been copied in response to copying the first copy of the logical volume to the second copy of the logical volume, wherein one data unit is determined to be at the first copy of the logical volume if the data unit is indicated as not copied to the second copy of the logical volume, and wherein one data that is determined to be at the second coy of the logical volume if the data unit is indicated as having been copied to the second copy of the logical volume.