Method, system, and program for transferring data

• US 20040148479A1
• Filed: 01/29/2003
• Published: 07/29/2004
• Est. Priority Date: 01/29/2003
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Patel, Vishal, Cheng, Tu-An
• Granted Patent: US 6,981,117 B2
• Time in Patent Office: Days
• US Class Current: 711/163
• CPC Class Codes: G06F 3/0617 in relation to availability
• 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 program for transferring data from a source storage unit, wherein storage units are configured within a storage system. A data transfer operation is processed to transfer data from source storage blocks in a source storage unit to corresponding target storage blocks in a target storage unit. For each source storage block, before transferring data from one source storage block to the corresponding target storage block, indication is made that the source storage block is in a locked state. Data in the source storage block in the locked state is not accessible to a host data request, and wherein data in storage blocks that are not in the locked state is accessible to a host data request while the data transfer operation is pending. Indication is further made that the source storage block is not in the locked state after transferring the data in the source storage block to the corresponding target storage block the data in the source storage block to the corresponding target storage block.

Claims

1. A method for transferring data from a source storage unit, wherein storage units are configured within a storage system, comprising:

processing a data transfer operation to transfer data from source storage blocks in a source storage unit to corresponding target storage blocks in a target storage unit; and

for each source storage block, performing;

(ii) before transferring data from one source storage block to the corresponding target storage block, indicating that the source storage block is in a locked state, wherein data in the source storage block in the locked state is not accessible to a host data request, and wherein data in storage blocks that are not in the locked state is accessible to a host data request while the data transfer operation is pending; and

(iii) indicating that the source storage block is not in the locked state after transferring the data in the source storage block to the corresponding target storage block.

2. The method of claim 1, wherein each storage block defines contiguous physical storage locations in the storage system.

3. The method of claim 2, wherein the logical storage units comprise logical volumes and the storage blocks comprise partitions.

4. The method of claim 1, wherein the storage blocks have a size such that any delayed access to the storage block due to being set to the locked state as part of a pending data transfer operation will have a minimal effect on host operations requesting the storage block.

5. The method of claim 4, wherein each storage block is approximately four to sixty-four megabytes in size.

6. The method of claim 1, wherein the data transfer operation comprises an operation to move data from the source storage unit to the target storage unit.

7. The method of claim 1, wherein storage units are organized into a plurality of storage pools, wherein each storage pool has different data storage characteristics, further comprising:

selecting the target storage unit, wherein the selected storage unit is in a same storage pool as the source storage unit.

8. The method of claim 7, wherein selecting the target storage unit further comprises determining one storage unit that is empty and in the same storage pool as the source storage unit.

9. The method of claim 1, further comprising:

in response to indicating that the storage block is in the locked state, invalidating metadata in each host cache including metadata on the storage block indicated in the locked state.

10. A method for processing data requests, comprising:

receiving a data request for requested data within a storage system, wherein data in the storage system is configured into a plurality of storage blocks, and wherein a lock is associated with each storage block indicating whether the storage block is being accessed as part of a pending data transfer operation;

determining whether the locks associated with the storage blocks that include the requested data indicate that the storage blocks are being accessed as part of one pending data transfer operation; and

accessing the requested data to return to the data request if the locks associated with the storage blocks that include the requested data do not indicate that at least one of the storage blocks are being accessed as part of one pending data transfer operation.

11. The method of claim 10, further comprising:

delaying processing of the data request if the locks associated with the storage blocks that include the requested data indicate that at least one of the storage blocks are being accessed as part of one pending data transfer operation.

12. The method of claim 11, wherein the processing of the data request is delayed until the locks of the storage blocks including the requested data indicate that the storage blocks are not being accessed as part of one pending data transfer operation.

13. The method of claim 11, wherein delaying the processing of the data request comprises adding the data request to a queue, further comprising:

processing one queued data requests if the locks associated with the storage blocks including the requested data for the queued data request indicate that the storage blocks are not being accessed as part of one pending data transfer operation.

14. A system for transferring data from a source storage unit, wherein storage units are configured within a storage system, comprising:

means for processing a data transfer operation to transfer data from source storage blocks in a source storage unit to corresponding target storage blocks in a target storage unit; and

means for performing for each source storage block;

(ii) before transferring data from one source storage block to the corresponding target storage block, indicating that the source storage block is in a locked state, wherein data in the source storage block in the locked state is not accessible to a host data request, and wherein data in storage blocks that are not in the locked state is accessible to a host data request while the data transfer operation is pending; and

(iii) indicating that the source storage block is not in the locked state after transferring the data in the source storage block to the corresponding target storage block.

15. The system of claim 14, wherein the storage blocks have a size such that any delayed access to the storage block due to being set to the locked state as part of a pending data transfer operation will have a minimal effect on host operations requesting the storage block.

16. The system of claim 14, wherein storage units are organized into a plurality of storage pools, wherein each storage pool has different data storage characteristics, further comprising:

means for selecting the target storage unit, wherein the selected storage unit is in a same storage pool as the source storage unit.

17. The system of claim 14, further comprising:

means for invalidating metadata in each host cache including metadata on the storage block indicated in the locked state in response to indicating that the storage block is in the locked state.

18. A system for processing data requests to data within a storage system configured into a plurality of storage blocks, comprising:

means for receiving a data request for requested data within a storage system;

means for associating a with each storage block indicating whether the storage block is being accessed as part of a pending data transfer operation;

means for determining whether the locks associated with the storage blocks that include the requested data indicate that the storage blocks are being accessed as part of one pending data transfer operation; and

means for accessing the requested data to return to the data request if the locks associated with the storage blocks that include the requested data do not indicate that at least one of the storage blocks are being accessed as part of one pending data transfer operation.

19. The system of claim 18, further comprising:

means for delaying processing of the data request if the locks associated with the storage blocks that include the requested data indicate that at least one of the storage blocks are being accessed as part of one pending data transfer operation.

20. The method of claim 19, wherein the means for delaying the processing of the data request adds the data request to a queue, further comprising:

means for processing one queued data requests if the locks associated with the storage blocks including the requested data for the queued data request indicate that the storage blocks are not being accessed as part of one pending data transfer operation.

21. An article of manufacture for transferring data from a source storage unit, wherein storage units are configured within a storage system, wherein the article of manufacture causes operations to be performed, the operations comprising:

processing a data transfer operation to transfer data from source storage blocks in a source storage unit to corresponding target storage blocks in a target storage unit; and

for each source storage block, performing;

(ii) before transferring data from one source storage block to the corresponding target storage block, indicating that the source storage block is in a locked state, wherein data in the source storage block in the locked state is not accessible to a host data request, and wherein data in storage blocks that are not in the locked state is accessible to a host data request while the data transfer operation is pending; and

(iii) indicating that the source storage block is not in the locked state after transferring the data in the source storage block to the corresponding target storage block.

22. The article of manufacture of claim 21, wherein each storage block defines contiguous physical storage locations in the storage system.

23. The article of manufacture of claim 22, wherein the logical storage units comprise logical volumes and the storage blocks comprise partitions.

24. The article of manufacture of claim 21, wherein the storage blocks have a size such that any delayed access to the storage block due to being set to the locked state as part of a pending data transfer operation will have a minimal effect on host operations requesting the storage block.

25. The article of manufacture of claim 24, wherein each storage block is approximately four to sixty-four megabytes in size.

26. The article of manufacture of claim 21, wherein the data transfer operation comprises an operation to move data from the source storage unit to the target storage unit.

27. The article of manufacture of claim 21, wherein storage units are organized into a plurality of storage pools, wherein each storage pool has different data storage characteristics, further comprising:

selecting the target storage unit, wherein the selected storage unit is in a same storage pool as the source storage unit.

28. The article of manufacture of claim 27, wherein selecting the target storage unit further comprises determining one storage unit that is empty and in the same storage pool as the source storage unit.

29. The article of manufacture of claim 21, further comprising:

in response to indicating that the storage block is in the locked state, invalidating metadata in each host cache including metadata on the storage block indicated in the locked state.

30. An article of manufacture for processing data requests, wherein the article of manufacture causes operations to be performed, the operations comprising:

receiving a data request for requested data within a storage system, wherein data in the storage system is configured into a plurality of storage blocks, and wherein a lock is associated with each storage block indicating whether the storage block is being accessed as part of a pending data transfer operation;

determining whether the locks associated with the storage blocks that include the requested data indicate that the storage blocks are being accessed as part of one pending data transfer operation; and

accessing the requested data to return to the data request if the locks associated with the storage blocks that include the requested data do not indicate that at least one of the storage blocks are being accessed as part of one pending data transfer operation.

31. The article of manufacture of claim 30, further comprising:

delaying processing of the data request if the locks associated with the storage blocks that include the requested data indicate that at least one of the storage blocks are being accessed as part of one pending data transfer operation.

32. The article of manufacture of claim 31, wherein the processing of the data request is delayed until the locks of the storage blocks including the requested data indicate that the storage blocks are not being accessed as part of one pending data transfer operation.

33. The article of manufacture of claim 32, wherein delaying the processing of the data request comprises adding the data request to a queue, further comprising:

processing one queued data requests if the locks associated with the storage blocks including the requested data for the queued data request indicate that the storage blocks are not being accessed as part of one pending data transfer operation.