METHOD, DEVICE, AND COMPUTER READABLE STORAGE MEDIUM FOR MANAGING STORAGE SYSTEM

• US 20200133560A1
• Filed: 09/24/2019
• Published: 04/30/2020
• Est. Priority Date: 10/30/2018
• Status: Active Grant

• Current Assignee: Emc IP Holding Company LLC (Dell Technologies Inc.)
• Original Assignee: Emc IP Holding Company LLC (Dell Technologies Inc.)
• Inventors: Wang, Hao, Zhang, Yang, Wu, Junfeng, Tan, Jiang
• Granted Patent: US 10,976,954 B2
• Time in Patent Office: Days
• CPC Class Codes: G06F 3/0604 Improving or facilitating administration, e.g. storage management
• CPC Class Codes: G06F 3/0608 Saving storage space on storage systems
• CPC Class Codes: G06F 3/0652 Erasing, e.g. deleting, data cleaning, moving of data to a wastebasket
• CPC Class Codes: G06F 3/0671 In-line storage system
• CPC Class Codes: G06F 3/0673 Single storage device

Abstract

Techniques involve managing a storage system. Along these lines, for each of a plurality of snapshots, a plurality of blocks referenced by the snapshot is determined. An evaluation score indicating an impact that deletion of the snapshot has on space release and data retention is determined based on at least one of: a reference count for the plurality of blocks, a size of a storage resource associated with the snapshot, and the number of blocks of the plurality of blocks that are referenced only once. At least one snapshot to be deleted is selected from the plurality of snapshots based on respective evaluation scores of the plurality of snapshots.

Claims

1. A method of managing a storage system, comprising:

determining, for each of a plurality of snapshots, a plurality of blocks referenced by the snapshot;

determining an evaluation score indicating an impact that deletion of the snapshot has on space release and data retention based on at least one of;

a reference count for the plurality of blocks, a size of a storage resource associated with the snapshot, and the number of blocks of the plurality of blocks that are referenced only once; and

selecting at least one snapshot to be deleted from the plurality of snapshots based on respective evaluation scores of the plurality of snapshots.

2. The method of claim 1, wherein determining the plurality of blocks comprises sampling the snapshot to determine the plurality of blocks.

3. The method of claim 1, wherein the evaluation score is positively correlated with a sum of reference counts for the plurality of blocks, and wherein the evaluation score is negatively correlated with the number of the blocks that are referenced only once and the size of the storage resource.

4. The method of claim 3, wherein selecting the at least one snapshot comprises:

in response to determining that a free space first policy is enabled, determining at least one snapshot of the plurality of snapshots that has a minimum evaluation score.

5. The method of claim 3, wherein selecting the at least one snapshot comprises:

in response to determining that a data retention first policy is enabled, determining at least one snapshot of the plurality of snapshots that has a maximum evaluation score.

6. A device for managing a storage system, comprising:

a processing unit;

a memory coupled to the processing unit and comprising instructions stored thereon, the instructions, when executed by the processing unit, causing the apparatus to perform acts comprising;

determining, for each of a plurality of snapshots, a plurality of blocks referenced by the snapshot;

determining an evaluation score indicating an impact that deletion of the snapshot has on space release and data retention based on at least one of;

a reference count for the plurality of blocks, a size of a storage resource associated with the snapshot, and the number of blocks of the plurality of blocks that are referenced only once; and

selecting at least one snapshot to be deleted from the plurality of snapshots based on respective evaluation scores of the plurality of snapshots. The device of claim 6, wherein determining the plurality of blocks comprises sampling the snapshot to determine the plurality of blocks.

8. The device of claim 6, wherein the evaluation score is positively correlated with a sum of reference counts for the plurality of blocks, and wherein the evaluation score is negatively correlated with the number of the blocks that are referenced only once and the size of the storage resource.

9. The device of claim 8, wherein selecting the at least one snapshot comprises:

in response to determining that a free space first policy is enabled, determining at least one snapshot of the plurality of snapshots that has a minimum evaluation score.

10. The device of claim 8, wherein selecting the at least one snapshot comprises:

in response to determining that a data retention first policy is enabled, determining at least one snapshot of the plurality of snapshots that has a maximum evaluation score.

11. A computer program product having a non-transitory computer readable medium which stores a set of instructions to manage a storage system;

the set of instructions, when carried out by computerized circuitry, causing the computerized circuitry to perform a method of;

determining, for each of a plurality of snapshots, a plurality of blocks referenced by the snapshot;

determining an evaluation score indicating an impact that deletion of the snapshot has on space release and data retention based on at least one of;

a reference count for the plurality of blocks, a size of a storage resource associated with the snapshot, and the number of blocks of the plurality of blocks that are referenced only once; and

selecting at least one snapshot to be deleted from the plurality of snapshots based on respective evaluation scores of the plurality of snapshots.