COMPRESSION-AWARE DATA STORAGE TIERING

• US 20130006948A1
• Filed: 06/30/2011
• Published: 01/03/2013
• Est. Priority Date: 06/30/2011
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: SHMUELI, Edi
• Granted Patent: US 8,527,467 B2
• Time in Patent Office: Days
• US Class Current: 707/693
• CPC Class Codes: G06F 16/1744 using compression, e.g. sparse files
• CPC Class Codes: G06F 16/185 Hierarchical storage management [HSM] systems, e.g. file migration or policies thereof details of archiving G06F16/11

Abstract

A method, including assigning, to each tier in a storage system comprising multiple tiers, a respective range of priority scores, and calculating a compression ratio for a file stored on one of the multiple tiers. Using the compression ratio, a priority score is calculated for the file, and the file is migrated to the tier whose assigned range of priority scores includes the calculated priority score.

Claims

1. A method, comprising:

assigning, to each tier in a storage system comprising multiple tiers, a respective range of priority scores, the multiple tiers including a higher performance storage tier and a lower performance storage tier;

calculating a compression ratio for a file stored on one of the multiple tiers;

calculating, using the compression ratio, a priority score for the file, wherein a higher compression ratio indicates less compressible data and a lower compression ratio indicates more highly compressible data; and

migrating the file to the tier whose assigned range of priority scores includes the calculated priority score wherein the higher performance storage tier is assigned a first range of priority scores including the higher compression ratio to thereby store the less compressible data and the lower performance storage tier is assigned a second range of priority scores including the lower compression ratio to thereby store the more highly compressible data.

2. The method, according to claim 1, wherein each of the multiple tiers comprises one or more storage devices.

3. The method according to claim 2, wherein each of the storage devices is assigned to each of the tiers based on performance of the each of the storage devices.

4. The method according to claim 1, wherein the priority score comprises a calculation using the compression ratio, a usage frequency, and a tunable parameter configured to set weights for the compression ratio and the usage frequency.

5. The method according to claim 1, wherein the respective ranges comprise contiguous and non-overlapping numeric ranges.

6. An apparatus, comprising:

a memory;

a storage system comprising multiple tiers, the multiple tiers including a higher performance storage tier and a lower performance storage tier; and

a processor in communication with the memory configured to assign, to each of the tiers, a respective range of priority scores, to calculate a compression ratio for a file stored on one of the multiple tiers, wherein a higher compression ratio indicates less compressible data and a lower compression ratio indicates more highly compressible data, to calculate, using the compression ratio, a priority score for the file, and to migrate the file to the tier whose assigned range of priority scores includes the calculated priority score, wherein the higher performance storage tier is assigned a first range of priority scores including the higher compression ratio to thereby store the less compressible data and the lower performance storage tier is assigned a second range of priority scores including the lower compression ratio to thereby store the more highly compressible data.

7. The apparatus according to claim 6, wherein each of the multiple tiers comprises one or more storage devices.

8. The apparatus according to claim 7, wherein the processor is configured to assign each of the storage devices to each of the tiers based on performance of the each of the storage devices.

9. The apparatus according to claim 6, wherein the processor is configured to calculate the priority score using the compression ratio, a usage frequency, and a tunable parameter configured to set weights for the compression ratio and the usage frequency.

10. The apparatus according to claim 6, wherein the respective ranges comprise contiguous and non-overlapping numeric ranges.

11. A computer program product, the computer program product comprising:

a non-transitory computer readable storage medium having computer readable program code embodied therewith, the computer readable program code comprising;

computer readable program code configured to assign, to each tier in a storage system comprising multiple tiers, a respective range of priority scores, the multiple tiers including a higher performance storage tier and a lower performance storage tier;

computer readable program code configured to calculate a compression ratio for a file stored on one of the multiple tiers, wherein a higher compression ratio indicates less compressible data and a lower compression ratio indicates more highly compressible data;

computer readable program code configured to calculate, using the compression ratio, a priority score for the file; and

computer readable program code configured to migrate the file to the tier whose assigned range of priority scores includes the calculated priority score, wherein the higher performance storage tier is assigned a first range of priority scores including the higher compression ratio to thereby store the less compressible data, and the lower performance storage tier is assigned a second range of priority scores including the lower compression ratio to thereby store the more highly compressible data.

12. The computer program product according to claim 11, wherein each of the multiple tiers comprises one or more storage devices.

13. The computer program product according to claim 12, wherein the computer readable program code is configured to assign each of the storage devices to each of the tiers based on performance of the each of the storage devices.

14. The computer program product according to claim 11, wherein the computer readable program code is configured to calculate the priority score using the compression ratio, a usage frequency, and a tunable parameter configured to set weights for the compression ratio and the usage frequency.

15. The computer program product according to claim 11, wherein the respective ranges comprise contiguous and non-overlapping numeric ranges.