Method, device and computer program product for managing extent in storage system

Patent metadata

Field	Value
Publication number	US-11995358-B2
Application number	US-202217826396-A
Country	US
Kind code	B2
Filing date	May 27, 2022
Priority date	Oct 21, 2021
Publication date	May 28, 2024
Grant date	May 28, 2024

Abstract

Techniques manage extents in a storage system having storage devices supporting a redundant storage strategy. A reserved area of the storage system is generated based on a set of first-type reserved extents respectively located in the storage devices, and the set of first-type reserved extents supports a reconstruction operation for a failed storage device when the failed storage device appears in the storage devices. A data area is generated based on a set of data extents respectively located outside the reserved area in the storage devices, and the data area provides data storage for a user. Here, a reserved extent size of the set of first-type reserved extents is smaller than a data extent size of data extents in the data area of the set of data extents. The quantity of extents can be reduced, thereby reducing overhead of storage and computing resources involved by associated metadata.

First claim

The invention claimed is:

1. A method for managing extents in a storage system which comprises a plurality of storage devices supporting a redundant storage strategy, the method comprising:
dividing each of the plurality of storage devices into a set of first-type reserved extents and a set of data extents, the data extents having a data extent size;
generating a reserved area of the storage system based at least on the set of first-type reserved extents respectively located in the plurality of storage devices, the set of first-type reserved extents being used for supporting a reconstruction operation for a failed storage device when the failed storage device appears in the plurality of storage devices;
generating a data area of the storage system based on the set of data extents respectively located outside the reserved area in the plurality of storage devices, the data area being used for providing data storage for a user of the storage system; and
performing the reconstruction operation for the failed storage device, the performing of the reconstruction operation including selecting the first-type reserved extents in the reserved area having smaller reserved extent size than the data extent size of the data extents in the data area, and reconstructing the extents in the failed storage device with the selected first-type reserved extents having the smaller reserved extent size.

2. The method according to claim 1 , wherein generating the reserved area comprises:
determining a maximum size of the first-type reserved extent;
determining a minimum quantity of the first-type reserved extents in a storage device of the plurality of storage devices; and
selecting, based on the maximum size and the minimum quantity, at least one first-type reserved extent from the storage device for generating the reserved area.

3. The method according to claim 2 , wherein determining the maximum size comprises:
determining a maximum quantity of the plurality of storage devices corresponding to the redundant storage strategy; and
determining the maximum size of the first-type reserved extent based on the maximum quantity and a capacity of the storage device.

4. The method according to claim 2 , wherein determining the minimum quantity comprises:
determining the minimum quantity based on a predetermined capacity of the reserved area and the maximum size of the first-type reserved extent.

5. The method according to claim 4 , further comprising:
dividing each of the plurality of storage devices into a set of second-type reserved extents,
wherein generating the reserved area further comprises:
generating the reserved area based on the set of second-type reserved extents respectively located in the plurality of storage devices, the set of second-type reserved extents being used for supporting an expansion operation in the storage system when the quantity of the plurality of storage devices changes.

6. The method according to claim 5 , wherein generating the reserved area based on the set of second-type reserved extents comprises:
determining, based on a minimum quantity of the plurality of storage devices corresponding to the storage strategy, the quantity of second-type reserved extents located in the storage devices.

7. The method according to claim 6 , wherein the second-type reserved extents and the first-type reserved extents have the same smaller reserved extent size, wherein the generating of the reserved area further comprises:
for the storage device, determining the quantity of reserved extents located in the storage device based on a sum of the minimum quantity of the first-type reserved extents and the quantity of the second-type reserved extents, and
wherein the method further comprises:
performing the expansion operation in the storage system, the performing of the expansion operation including adding a storage device to the plurality of storage devices, and, having added the storage device to the plurality of storage devices, determining whether a resulting quantity of the plurality of storage devices is greater than, equal to, or less than a RAID width of the storage system;
if the resulting quantity of the plurality of storage devices is greater than or equal to the RAID width, constructing a RAID stripe that spans the plurality of storage devices while avoiding migrating data inside the storage system; and
if the resulting quantity of the plurality of storage devices is less than the RAID width, constructing a RAID stripe that meets the RAID width by migrating data inside the storage system.

8. The method according to claim 2 , wherein generating the data area comprises:
determining a maximum value of the data extent size based on a multiple of the maximum size of the reserved extent; and
based on a capacity of a storage device in the plurality of storage devices and the maximum value of the data extent size, determining a data extent quantity of data extents located in the storage device.

9. The method according to claim 8 , wherein determining the data extent quantity of data extents located in the storage device further comprises:
determining a predetermined condition associated with the data extent quantity based on a minimum quantity of the plurality of storage devices corresponding to the storage strategy; and
determining the data extent quantity based on the capacity of the storage device in the plurality of storage devices, the maximum value, and the predetermined condition.

10. The method according to claim 9 , wherein the predetermined condition comprises that:
the data extent quantity is an integer multiple of the minimum quantity of the plurality of storage devices corresponding to the storage strategy.

11. An electronic device, including:
at least one processor;
a volatile memory; and
a memory coupled to the at least one processor, wherein the memory has instructions stored therein which, when executed by the at least one processor, cause the device to perform actions for managing extents in a storage system that comprises a plurality of storage devices supporting a redundant storage strategy, and the actions comprise:
dividing each of the plurality of storage devices into a set of first-type reserved extents and a set of data extents, the data extents having a data extent size;
generating a reserved area of the storage system based at least on the set of first-type reserved extents respectively located in the plurality of storage devices, the set of first-type reserved extents being used for supporting a reconstruction operation for a failed storage device when the failed storage device appears in the plurality of storage devices;
generating a data area of the storage system based on the set of data extents respectively located outside the reserved area in the plurality of storage devices, the data area being used for providing data storage for a user of the storage system; and
performing the reconstruction operation for the failed storage device, the performing of the reconstruction operation including selecting the first-type reserved extents in the reserved area having a smaller reserved extent size than the data extent size of the data extents in the data area, and

reconstructing the extents in the failed storage device with the selected first-type reserved extents having the smaller reserved extent size.

12. The device according to claim 11 , wherein generating the reserved area comprises:
determining a maximum size of the first-type reserved extent;
determining a minimum quantity of the first-type reserved extents in a storage device of the plurality of storage devices; and
determining, based on the maximum size and th

Assignees

• Emc Ip Holding Co Llc

Inventors

• Wang Sheng
• Chen Huan
• Chi Dapeng
• Liu Wenyang
• Tian Ying

Classifications

• G06F3/0689 Primary

  Disk arrays, e.g. RAID, JBOD · CPC title

• G06F3/0619

  in relation to data integrity, e.g. data losses, bit errors · CPC title

• G06F3/0631

  by allocating resources to storage systems · CPC title

• G06F3/065

  Replication mechanisms · CPC title

• G06F3/067

  Distributed or networked storage systems, e.g. storage area networks [SAN], network attached storage [NAS] · CPC title