Method, device, and computer readable storage medium for managing storage system

Patent metadata

Field	Value
Publication number	US-10976954-B2
Application number	US-201916579987-A
Country	US
Kind code	B2
Filing date	Sep 24, 2019
Priority date	Oct 30, 2018
Publication date	Apr 13, 2021
Grant date	Apr 13, 2021

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.

First claim

We claim:

1. A method of managing a storage system, comprising:
determining, for each of a plurality of snapshots, a plurality of blocks referenced by that snapshot;
determining, for each of the plurality of snapshots, an evaluation score indicating an impact that deletion of that snapshot has on space release and data retention based on at least one of: a reference count for the plurality of blocks referenced by that snapshot, a size of a storage resource associated with that snapshot, and the number of blocks of the plurality of blocks referenced by that snapshot that are referenced only once, wherein the evaluation score of each of the plurality of snapshots is:
(a) positively correlated with a sum of reference counts for the plurality of blocks referenced by that snapshot and
(b) negatively correlated with the number of the blocks referenced by that snapshot that are referenced only once and the size of the storage resource associated with that snapshot; 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 that snapshot to determine the plurality of blocks.

3. The method of claim 1 , 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.

4. The method of claim 1 , 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.

5. 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 that snapshot;
determining, for each of the plurality of snapshots, an evaluation score indicating an impact that deletion of that snapshot has on space release and data retention based on at least one of: a reference count for the plurality of blocks referenced by that snapshot, a size of a storage resource associated with that snapshot, and the number of blocks of the plurality of blocks referenced by that snapshot that are referenced only once, wherein the evaluation score of each of the plurality of snapshots is:
(a) positively correlated with a sum of reference counts for the plurality of blocks referenced by that snapshot and
(b) negatively correlated with the number of the blocks referenced by that snapshot that are referenced only once and the size of the storage resource associated with that snapshot; and

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

6. The device of claim 5 , wherein determining the plurality of blocks comprises sampling that snapshot to determine the plurality of blocks.

7. The device of claim 5 , 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.

8. The device of claim 5 , 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.

9. 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 that snapshot;
determining, for each of the plurality of snapshots, an evaluation score indicating an impact that deletion of that snapshot has on space release and data retention based on at least one of: a reference count for the plurality of blocks referenced by that snapshot, a size of a storage resource associated with that snapshot, and the number of blocks of the plurality of blocks referenced by that snapshot that are referenced only once, wherein the evaluation score of each of the plurality of snapshots is:
(a) positively correlated with a sum of reference counts for the plurality of blocks referenced by that snapshot and
(b) negatively correlated with the number of the blocks referenced by that snapshot that are referenced only once and the size of the storage resource associated with that snapshot; and

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

10. The computer program product of claim 9 , wherein determining the plurality of blocks comprises sampling that snapshot to determine the plurality of blocks.

11. The computer program product of claim 9 , 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.

12. The computer program product of claim 9 , 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.

Assignees

• Emc Ip Holding Co Llc

Inventors

• Wang Hao
• Zhang Yang
• Wu Junfeng
• Tan Jiang

Classifications

• G06F3/0671

  In-line storage system · CPC title

• G06F3/0652 Primary

  Erasing, e.g. deleting, data cleaning, moving of data to a wastebasket · CPC title

• G06F3/0604

  Improving or facilitating administration, e.g. storage management · CPC title

• G06F11/1448 Primary

  Management of the data involved in backup or backup restore · CPC title

• G06F3/0673

  Single storage device · CPC title