Systems and methods for using thin provisioning to reclaim space identified by data reduction processes

• US 8,332,612 B1
• Filed: 03/05/2012
• Issued: 12/11/2012
• Est. Priority Date: 12/18/2009
• Status: Active Grant

• Current Assignee: Emc IP Holding Company LLC (Dell Technologies Inc.)
• Original Assignee: EMC Corporation (Dell Technologies Inc.)
• Inventors: Raizen, Helen S., Bappe, Michael E., Nikolaevich, Agarkov Vadim, Biester, William Carl, Ruef, Richard, Owen, Karl M.
• Primary Examiner(s): PORTKA, GARY J
• Application Number:
  US13/411,936
• Time in Patent Office: 281 Days
• Field of Search: None
• US Class Current: 711/202
• CPC Class Codes: G06F 3/0608 Saving storage space on storage systems
• CPC Class Codes: G06F 3/0641 De-duplication techniques
• CPC Class Codes: G06F 3/0665 at area level, e.g. provisioning of virtual or logical volumes
• CPC Class Codes: G06F 3/0689 Disk arrays, e.g. RAID, JBOD

Abstract

The invention provides a system to reclaim space identified as no longer in use and comprises a vLUN, a thinly provisioned mapped LUN, a mapping layer, and a data reduction engine. Chunks of data are stored at logical chunk addresses (LCAs) in the vLUN and are mapped to corresponding physical chunk addresses (PCAs) in the thinly provisioned mapped LUN. The data reduction engine performs a data reduction process on a first logical chunk of data stored at a first LCA in the vLUN, where the first logical chunk has a size that is a nonzero integer multiple of the size of the storage extent of the thinly provisioned mapped LUN. After the data reduction process, the PCA associated with the first logical chunk is no longer needed, and the thinly provisioned mapped LUN is instructed to deallocate the PCA associated with the first logical chunk that is no longer needed.

Claims

1. An apparatus for reclaiming storage space identified as no longer in use, the apparatus comprising:

a virtual logic unit (vLUN) layer constructed and arranged to be part of the input/output (I/O) path of a computer system, the vLUN configured to provide a plurality of logical chunk addresses (LCAs) to layers disposed above it;

a thinly provisioned mapped logical unit (mapped LUN) layer disposed below and in operable communication with the vLUN layer, the thinly provisioned mapped LUN being in operable communication with a pool of storage units that provide, as requested, storage space to the thinly provisioned mapped LUN, wherein the mapped LUN is associated with a plurality of physical chunk addresses (PCAs), each PCA configured to provide physical storage for a respective chunk of data; and

a data reduction engine in operable communication with the vLUN, the data reduction engine configured to;

perform a data reduction process on a first logical chunk of data stored in the vLUN at a first LCA and associated with a first PCA;

remap the first LCA to a second PCA in a second region of the mapped LUN such that a first PCA in a first region of the mapped LUN is no longer required for storage of a first logical chunk of data and is therefore a first unneeded chunk, wherein;

the first region on the mapped LUN comprises a set of first PCAs, each first PCA being allotted to provide physical storage for a respective first chunk of data stored at a single first corresponding LCA in the vLUN; and

wherein the second region of the mapped LUN comprises a set of second PCAs, each second PCA being allotted to provide physical storage for a respective second chunk of data, where the second chunk of data corresponds to data that is associated with at least two LCAs; and

instruct the thinly provisioned mapped LUN to deallocate the first PCA associated with the first unneeded chunk.

2. The apparatus of claim 1, further comprising a mapping layer, the mapping layer comprising a first portion indicating, for each LCA in the vLUN, whether the corresponding PCA for the LCA is in the first region or the second region of the mapped LUN, and a second portion providing, if the corresponding PCA is in the second region of the mapped LUN, mapping information for the LCA to the corresponding PCA in the second region.

3. The apparatus of claim 2, wherein the first portion is stored in at least one of memory of the computer system or in a fast media accessible to the computer system, to help improve the efficiency of I/O access to the chunks of data stored in the mapped LUN.

4. The apparatus of claim 1, wherein the mapped LUN has a minimum size of storage that it can be directed to allocate or deallocate from the pool of storage units, and wherein the first logical chunk of data has a size that is a nonzero integer multiple of the first minimum size.

5. The apparatus of claim 1, wherein the mapped LUN has a minimum size of storage that it can be directed to allocate or deallocate from the pool of storage units and wherein the first logical chunk of data has a size that is greater than or equal to the first minimum size.

6. The apparatus of claim 1, wherein the data reduction engine comprises at least one of a deduplication engine and a compression engine.

7. The apparatus of claim 6, wherein the mapped LUN has a minimum size of storage that it can be directed to allocate or deallocate from the pool or storage units, and wherein the at least one of the deduplication engine and the compression engine is operable on a data reduction chunk of data having a size that is a nonzero integer multiple of the minimum size.

8. The apparatus of claim 1, wherein the mapped LUN is implemented as part of the pool of storage units.

9. The apparatus of claim 1, wherein the mapped LUN is implemented as part of a computer system.

10. An apparatus usable with a computer system to reclaim storage space identified as no longer in use, the apparatus comprising:

a virtual logic unit (vLUN) layer constructed and arranged to be part of the input/output (I/O) path of the computer system, the vLUN configured to provide a plurality of logical chunk addresses (LCAs) to layers disposed above it;

a thinly provisioned mapped logical unit (mapped LUN) layer disposed below and in operable communication with the vLUN layer, the thinly provisioned mapped LUN being in operable communication with a pool of storage units that provide, as requested, storage space to the thinly provisioned mapped LUN, wherein the mapped LUN is associated with a plurality of physical chunk addresses (PCAs), each PCA configured to provide physical storage for a respective chunk of data;

a mapping layer disposed between and in operable communication with the vLUN and the mapped LUN, the mapping layer configured to;

define first and second regions on the mapped LUN, the first region comprising a set of first PCAs, each first PCA being allotted to provide physical storage for a respective first chunk of data stored at a single first corresponding LCA in the vLUN, the second region comprising a set of second PCAs, each second PCA being allotted to provide physical storage for a respective second chunk of data, where the second chunk of data corresponds to data that is associated with at least two LCAs;

indicate, for each LCA in the vLUN, whether the corresponding PCA for the LCA is in the first region or the second region of the mapped LUN; and

provide, if the corresponding PCA is in the second region of the mapped LUN, mapping information for the LCA to the corresponding PCA in the second region; and

a data reduction engine in operable communication with the vLUN, the data reduction engine configured to;

perform a data reduction process on a first logical chunk of data stored in the vLUN at a first LCA and associated with a first PCA;

remap the first LCA to a second PCA in the second region, such that the first PCA in the first region is no longer required for storage of the first logical chunk of data and is therefore a first unneeded chunk; and

instruct the thinly provisioned mapped LUN to deallocate the first PCA associated with the first unneeded chunk.

11. The apparatus of claim 10, wherein the mapped LUN has a first minimum size of storage that it can be directed to allocate or deallocate, and wherein the first logical chunk of data is a nonzero integer multiple of the first minimum size.

12. The apparatus of claim 10, wherein the data reduction engine further comprises at least one of a deduplication engine and a compression engine.

13. The apparatus of claim 10, wherein the first portion is stored in at least one of memory of the computer system or in a fast media accessible to the computer system, to help improve the efficiency of I/O access to the chunks of data stored in the mapped LUN.

14. A method for reclaiming storage space identified as no longer in use, the method comprising:

configuring a virtual logic unit (vLUN) layer to provide a plurality of logical chunk addresses (LCAs) to layers disposed above it, wherein the vLUN constructed and arranged to be one of a plurality of layers comprising the input/output (I/O) path of a computer system;

disposing a thinly provisioned mapped logical unit (mapped LUN) layer below and in operable communication with the vLUN layer, the thinly provisioned mapped LUN being in operable communication with a pool of storage units that provide, as requested, storage space to the thinly provisioned mapped LUN, wherein the mapped LUN is associated with a plurality of physical chunk addresses (PCAs), each PCA configured to provide physical storage for a respective chunk of data; and

configuring a data reduction engine to be in operable communication with the vLUN, wherein the data reduction engine is constructed and arranged to;

perform a data reduction process on a first logical chunk of data stored in the vLUN at a first LCA and associated with a first PCA;

remap the first LCA to a second PCA in a second region of the mapped LUN such that a first PCA in a first region of the mapped LUN is no longer required for storage of a first logical chunk of data and is therefore a first unneeded chunk, wherein;

the first region of the mapped LUN comprises a set of first PCAs, each first PCA being allotted to provide physical storage for a respective first chunk of data stored at a single first corresponding LCA in the vLUN; and

wherein the second region of the mapped LUN comprises a set of second PCAs, each second PCA being allotted to provide physical storage for a respective second chunk of data, where the second chunk of data corresponds to data that is associated with at least two LCAs; and

instruct the thinly provisioned mapped LUN to deallocate the first PCA associated with the first unneeded chunk.

15. The method of claim 14, further comprising providing a mapping layer, the mapping layer comprising a first portion indicating, for each LCA in the vLUN, whether the corresponding PCA for the LCA is in the first region or the second region of the mapped LUN, and a second portion providing, if the corresponding PCA is in the second region of the mapped LUN, mapping information for the LCA to the corresponding PCA in the second region.

16. The method of claim 15, wherein the first portion is stored in at least one of memory of the computer system or in a fast media accessible to the computer system, to help improve the efficiency of I/O access to the chunks of data stored in the mapped LUN.

17. The method of claim 14, further comprising storing in the memory of the computer system or in fast media accessible to the computer system, information indicating, for each LCA in the vLUN, whether the corresponding PCA for the LCA is in the first region or the second region of the mapped LUN.

18. The method of claim 14, further comprising disposing the mapped LUN so that it is part of the pool of storage units.

19. The method of claim 14, further comprising disposing the mapped LUN so that it is part of a computer system.

20. The method of claim 14, wherein the data reduction process comprises at least one of a deduplication process and a compression process.