EXTENT ALLOCATION IN THINLY PROVISIONED STORAGE ENVIRONMENT

• US 20110185147A1
• Filed: 01/27/2010
• Published: 07/28/2011
• Est. Priority Date: 01/27/2010
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: HATFIELD, Brian D., LOVRIEN, Kurt A.
• Granted Patent: US 8,639,876 B2
• Time in Patent Office: Days
• US Class Current: 711/170
• CPC Class Codes: G06F 3/061 Improving I/O performance
• CPC Class Codes: G06F 3/0631 by allocating resources to storage systems
• CPC Class Codes: G06F 3/0665 at area level, e.g. provisioning of virtual or logical volumes
• CPC Class Codes: G06F 3/067 Distributed or networked storage systems, e.g. storage area networks [SAN], network attached storage [NAS]

Abstract

Method, apparatus, and computer program product embodiment for allocating a plurality of extents in a thinly provisioned computing storage environment are provided. In one such embodiment, subsequent to a write request and previous to entering a cache of the computing storage environment, a determination is made, for a logical extent, whether a real extent is available. Pursuant to determining the availability of the real extent, the logical extent is allocated to the real extent by updating system metadata associated with the logical extent.

Claims

1. A method for allocating a plurality of extents in a thinly provisioned computing storage environment, comprising:

subsequent to a write request and previous to entering a cache of the computing storage environment, determining, for a logical extent, whether a real extent is available; and

pursuant to determining the availability of the real extent, allocating the logical extent to the real extent by updating system metadata associated with the logical extent.

2. The method of claim 1, further including, previous to determining the availability of the real extent, determining if the real extent is assigned to the logical extent, wherein if the real extent is not assigned to the logical extent, locating an available real extent in a storage pool in the thinly-provisioned computing storage environment, and assigning the available real extent the logical extent.

3. The method of claim 1, further including, subsequent to allocating the logical extent to the real extent, hardening the updated system metadata.

4. The method of claim 3, wherein hardening the updated system metadata is performed by initiating a background task.

5. The method of claim 4, further including, subsequent to hardening the updated system metadata, allocating space in the cache for data associated with the write request.

6. The method of claim 5, further including, previous to destaging the data associated with the write request to the allocated real extent, determining if the updated system metadata has been hardened, wherein if the updated system metadata has not been hardened, waiting for the background task to harden the updated system metadata to complete.

7. The method of claim 1, wherein allocating the logical extent to the real extent by updating system metadata associated with the logical extent is first performed for at least one of a plurality of volatile extent allocations.

8. The method of claim 7, further including, if allocating the logical extent to the real extent performed for the at least one of the plurality of volatile extent allocations has completed, allocating the logical extent to the real extent for at least one of a plurality of non-volatile extent allocations.

9. A system for allocating a plurality of extents in a thinly provisioned computing storage environment, comprising:

a processor operational within the thinly-provisioned computing storage environment, wherein the processor is adapted for;

subsequent to a write request and previous to entering a cache of the computing storage environment, determining, for a logical extent, whether a real extent is available, and

pursuant to determining the availability of the real extent, allocating the logical extent to the real extent by updating system metadata associated with the logical extent.

10. The system of claim 9, wherein the processor is further adapted for, previous to determining the availability of the real extent, determining if the real extent is assigned to the logical extent, wherein if the real extent is not assigned to the logical extent, locating an available real extent in a storage pool in the thinly-provisioned computing storage environment, and assigning the available real extent the logical extent.

11. The system of claim 9, wherein the processor is further adapted for, subsequent to allocating the logical extent to the real extent, hardening the updated system metadata.

12. The system of claim 11, wherein the processor is further adapted for initiating a background task to harden the updated system metadata.

13. The system of claim 12, wherein the processor is further adapted for, subsequent to hardening the updated system metadata, allocating space in the cache for data associated with the write request.

14. The system of claim 13, wherein the processor is further adapted for, previous to destaging the data associated with the write request to the allocated real extent, determining if the updated system metadata has been hardened, wherein if the updated system metadata has not been hardened, waiting for the background task to harden the updated system metadata to complete.

15. A computer program product for allocating a plurality of extents in a thinly provisioned computing storage environment, the computer program product comprising a computer-readable storage medium having computer-readable program code portions stored therein, the computer-readable program code portions comprising:

a first executable portion for, subsequent to a write request and previous to entering a cache of the computing storage environment, determining, for a logical extent, whether a real extent is available; and

a second executable portion for, pursuant to determining the availability of the real extent, allocating the logical extent to the real extent by updating system metadata associated with the logical extent.

16. The computer program product of claim 15, further including a third executable portion for, previous to determining the availability of the real extent, determining if the real extent is assigned to the logical extent, wherein if the real extent is not assigned to the logical extent, locating an available real extent in a storage pool in the thinly-provisioned computing storage environment, and assigning the available real extent the logical extent.

17. The computer program product of claim 15, further including a third executable portion for, subsequent to allocating the logical extent to the real extent, hardening the updated system metadata.

18. The computer program product of claim 17, further including a fourth executable portion for, pursuant to hardening the updated system metadata, initiating a background task.

19. The computer program product of claim 18, further including a fifth executable portion for, subsequent to hardening the updated system metadata, allocating space in the cache for data associated with the write request.

20. The computer program product of claim 19, further including a sixth executable portion for, previous to destaging the data associated with the write request to the allocated real extent, determining if the updated system metadata has been hardened, wherein if the updated system metadata has not been hardened, waiting for the background task to harden the updated system metadata to complete.