System and method for reclaiming unused space from a thinly provisioned data container

• US 20060085471A1
• Filed: 10/15/2004
• Published: 04/20/2006
• Est. Priority Date: 10/15/2004
• Status: Active Grant

• Current Assignee: NetApp, Inc.
• Original Assignee: NetApp, Inc.
• Inventors: Rajan, Vijayan, Doucette, Douglas P., Bolen, David Brittain
• Granted Patent: US 7,603,532 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 16/1727 Details of free space management performed by the file system saving storage space on storage systems G06F3/0608; management of blocks in storage devices G06F3/064
• CPC Class Codes: G06F 3/0608 Saving storage space on storage systems
• CPC Class Codes: G06F 3/0631 by allocating resources to storage systems
• CPC Class Codes: G06F 3/0643 Management of files
• 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]
• CPC Class Codes: H04L 67/1097 for distributed storage of data in networks, e.g. transport arrangements for network file system [NFS], storage area networks [SAN] or network attached storage [NAS]
• CPC Class Codes: Y10S 707/99953 Recoverability
• CPC Class Codes: Y10S 707/99957 Garbage collection

Abstract

A system and method for reclaims unused space from a thinly provision data container served by a storage system. A host-side agent detects blocks of the data container that may be freed and sends a novel Punch Hole command to the storage system associated with the data container. The storage system allocates the appropriate blocks in response to the Punch Hole command.

Claims

1. A method for reclaiming unused space from a thinly provisioned data container served by a storage system, the method comprising the steps of:

determining one or more sets of blocks no longer in use on the thinly provisioned data container;

sending a punch hole command to the storage system, the punch hole command identifying one or more sets of blocks no longer in use on the thinly provisioned data container; and

in response to receiving the punch hole command, deallocating the one or more sets of blocks identified in the punch hole command.

2. The method of claim 1 wherein the data container comprises a virtual disk.

3. The method of claim 1 wherein the punch hole command comprises a small computer systems interface vendor specific command.

4. The method of claim 1 wherein the punch hole command comprises an operation code field, a number of ranges field and one or more range identifier fields.

5. The method of claim 4 wherein the range identifier fields comprise a logical block address field and a range length field.

6. The method of claim 1 wherein the punch hole command comprises an operation code field, a bitmap size field, a logical block address field and a bitmap field.

7. The method of claim 1 wherein the step of determining one or more sets of blocks no longer in use on the data container further comprises the step of querying a file system on a client.

8. The method of claim 1 wherein the step of determining one or more sets of blocks no longer in use on the data container further comprises the steps of:

allocating a file on a file system overlaid onto the data container;

locking the allocated file;

identifying blocks storing the allocated file on the file system; and

identifying as the one or more sets of blocks no longer in use on the data container the identified blocks storing the allocated file.

9. The method of claim 1 wherein the step of determining one or more sets of blocks no longer in use on the data container comprises the step of querying a non-file system application utilizing the data container.

10. The method of claim 9 wherein the non-file system application comprises a database system.

11. A system for reclaiming unused space from a thinly provisioned data container served by a storage system, the system comprising:

means for determining one or more sets of blocks no longer in use on the thinly provisioned data container;

means for sending a punch hole command to the storage system, the punch hole command identifying one or more sets of blocks no longer in use on the thinly provisioned data container; and

means for in response to receiving the punch hole command, deallocating the one or more sets of blocks identified in the punch hole command.

12. The system of claim 11 wherein the data container comprises a virtual disk.

13. The system of claim 11 wherein the punch hole command comprises a small computer systems interface vendor specific command.

14. The system of claim 11 wherein the punch hole command comprises an operation code field, a number of ranges field and one or more range identifier fields.

15. The system of claim 14 wherein the range identifier fields comprise a logical block address field and a range length field.

16. The system of claim 11 wherein the punch hole command comprises an operation code field, a bitmap size field, a logical block address field and a bitmap field.

17. The system of claim 11 wherein the means for determining one or more sets of blocks no longer in use on the data container further comprises means for querying a file system on a client.

18. The system of claim 11 wherein the means for determining one or more sets of blocks no longer in use on the data container further comprises:

means for allocating a file on a file system overlaid onto the data container;

means for locking the allocated file;

means for identifying blocks storing the allocated file on the file system; and

means for identifying as the one or more sets of blocks no longer in use on the data container the identified blocks storing the allocated file.

19. The system of claim 11 wherein the means for determining one or more sets of blocks no longer in use on the data container further comprises means for querying a non-file system application utilizing the data container.

20. The system of claim 19 wherein the non-file system application comprises a database system.

21. A system for reclaiming unused space from a thinly provisioned data container served by a storage system, the system comprising:

a host-side agent executing on a client of the storage system hosting the thinly provisioned data container, the host-side agent adapted to determine blocks of the data container that are no longer in use by the client and to send a punch hole command to the storage system, wherein the punch hole command identifies the blocks of the data container that are no longer in use by the client.

22. The system of claim 21 wherein the host-side agent is further adapted to query a file system on the client to determine blocks of the data container that are no longer in use by the client.

23. The system of claim 21 wherein the host-side agent is further adapted to query a non-file system application to determine blocks of the data container that are no longer in use by the client.

24. A computer readable medium for reclaiming unused space from a thinly provisioned data container served by a storage system, the computer readable medium including program instructions for performing the steps of:

determining one or more sets of blocks no longer in use on the data container;

sending a punch hole command to the storage system, the punch hole command identifying one or more sets of blocks no longer in use on the data container; and

in response to receiving the punch hole command, de-allocating the one or more sets of blocks identified in the punch hole command.

25. A system for reclaiming unused space from a thinly provisioned data container served by a storage system, the system comprising:

a storage operating system executing on the storage system, the storage operating system adapted to receive a punch hole command from a host-side agent and further adapted to deallocate one or more ranges of blocks identified in the punch hole command.