Method, device and computer program product for managing metadata at a control device

Patent metadata

Field	Value
Publication number	US-10936489-B2
Application number	US-201916512644-A
Country	US
Kind code	B2
Filing date	Jul 16, 2019
Priority date	Jul 27, 2018
Publication date	Mar 2, 2021
Grant date	Mar 2, 2021

Abstract

Techniques for managing metadata at a control device involve: determining, from a cache page corresponding to user data, a first region for storing raw metadata of the user data, the raw metadata including address information for storing the user data in a storage system; in response to the user data being modified, determining updated metadata of the modified user data to update the raw metadata in the first region; and copying the updated metadata to a high-speed memory shared by the control device and another control device. Accordingly, the techniques are capable of reducing the usage frequency of the high-speed memory, thereby extending the service life of the high-speed memory and reducing cost.

First claim

We claim:

1. A method for managing metadata at a control device, comprising:
determining, from a cache page corresponding to user data, a first region for storing raw metadata of the user data, the raw metadata comprising address information for storing the user data in a storage system;
in response to the user data being modified, determining updated metadata of the modified user data to update the raw metadata in the first region;
copying the updated metadata to a high-speed memory shared by the control device and another control device;
in response to metadata stored on a second region of the cache page being updated, merging the first region and the second region into a third region; and
copying the metadata stored in the third region to the shared high-speed memory;

wherein merging the first region and the second region into a third region comprises:
determining a first starting position and a first length of the first region in the cache page;
determining a second starting position and a second length of the second region in the cache page;
determining a starting position of the third region based on the first starting position and the second starting position; and
determining a length of the third region, based on the first starting position, the first length, the second starting position, and the second length.

2. The method according to claim 1 , wherein determining the first region comprises:
determining the first region in the cache page for storing the raw metadata, based on description information of the cache page.

3. The method according to claim 1 , wherein determining updated metadata of the modified user data comprises:
determining, based on address mapping management information, address information of the modified user data stored in the storage system; and
generating the updated metadata based on the determined address information.

4. The method according to claim 1 , further comprising:
sending an update message to the another control device to inform the another control device to use the updated metadata that has been stored in the shared high-speed memory.

5. The method according to claim 1 , further comprising:
in response to receiving an access request for the user data, redirecting the access request to one of the control device and the another control device based on address information of the user data to be accessed.

6. A control device for managing metadata, comprising:
at least one processing unit;
at least one memory coupled to the at least one processing unit and storing instructions executed by the at least one processing unit, the instructions, when executed by the at least one processing unit, causing the control device to perform actions comprising:
determining, from a cache page corresponding to user data, a first region for storing raw metadata of the user data, the raw metadata including address information for storing the user data in a storage system;
in response to the user data being modified, determining updated metadata of the modified user data to update the raw metadata in the first region;
copying the updated metadata to a high-speed memory shared by the control device and another control device;
in response to metadata stored on a second region of the cache page being updated, merging the first region and the second region into a third region; and
copying the metadata stored in the third region to the shared high-speed memory;

wherein merging the first region and the second region into a third region comprises:
determining a first starting position and a first length of the first region in the cache page;
determining a second starting position and a second length of the second region in the cache page;
determining a starting position of the third region based on the first starting position and the second starting position; and
determining a length of the third region, based on the first starting position, the first length, the second starting position, and the second length.

7. The control device according to claim 6 , wherein determining the first region comprises:
determining the first region in the cache page for storing the raw metadata, based on description information of the cache page.

8. The control device according to claim 6 , wherein determining updated metadata of the modified user data comprises:
determining, based on address mapping management information, address information of the modified user data stored in the storage system; and
generating the updated metadata based on the determined address information.

9. The control device according to claim 6 , wherein the actions further comprise:
sending an update message to the another control device to inform the another control device to use the updated metadata that has been stored in the shared high-speed memory.

10. The control device according to claim 6 , wherein the actions further comprise:
in response to receiving an access request for the user data, redirecting the access request to one of the control device and the another control device based on address information of the user data to be accessed.

11. A computer program product having a non-transitory computer readable medium which stores a set of instructions to manage metadata at a control device; the set of instructions, when carried out by computerized circuitry, causing the computerized circuitry to perform a method of:
determining, from a cache page corresponding to user data, a first region for storing raw metadata of the user data, the raw metadata comprising address information for storing the user data in a storage system;
in response to the user data being modified, determining updated metadata of the modified user data to update the raw metadata in the first region;
copying the updated metadata to a high-speed memory shared by the control device and another control device;
in response to metadata stored on a second region of the cache page being updated, merging the first region and the second region into a third region; and
copying the metadata stored in the third region to the shared high-speed memory;

wherein merging the first region and the second region into a third region comprises:
determining a first starting position and a first length of the first region in the cache page;
determining a second starting position and a second length of the second region in the cache page;
determining a starting position of the third region based on the first starting position and the second starting position; and
determining a length of the third region, based on the first starting position, the first length, the second starting position, and the second length.

12. The computer program product according to claim 11 , wherein determining the first region comprises:
determining the first region in the cache page for storing the raw metadata, based on description information of the cache page.

13. The computer program product according to claim 11 , wherein determining updated metadata of the modified user data comprises:
determining, based on address mapping management information, address information of the modified user data stored in the storage system; and
generating the updated metadata based on the determined address information.

14. The computer program product according to claim 11 , wherein the method further includes:
sending an update message to the another control device to inform the another control device to use the updated metadata that has been stored in the shared high-speed memory.

15. The computer program product according to claim 11 , wher

Assignees

• Emc Ip Holding Co Llc

Inventors

• Han Geng
• Liu Yousheng
• Li Xiongcheng
• Yang Lifeng
• Kang Jianbin

Classifications

• G06F12/0868 Primary

  Data transfer between cache memory and other subsystems, e.g. storage devices or host systems · CPC title

• G06F2212/466

  Metadata, control data · CPC title

• G06F2212/282

  Partitioned cache · CPC title

• G06F2212/7201

  Logical to physical mapping or translation of blocks or pages · CPC title

• G06F12/084

  with a shared cache · CPC title