Method, device and computer program product for managing storage system

Patent metadata

Field	Value
Publication number	US-11288210-B2
Application number	US-201916356417-A
Country	US
Kind code	B2
Filing date	Mar 18, 2019
Priority date	Jul 20, 2018
Publication date	Mar 29, 2022
Grant date	Mar 29, 2022

Abstract

Techniques manage a storage system. In accordance with such techniques, an access request for target data is received; a storage position of the target data is determined, the storage position indicating one of a storage device and a cache; a target element corresponding to the target data is determined from a first replacement list and a second replacement list associated with the first replacement list based on the storage position, the first replacement list including at least a counting element, the counting element indicating an access count of data in the storage device, the second replacement list including a low-frequency access element, the low-frequency access element indicating a cache page with a low access frequency in the cache; and a position of the target element in a replacement list where the target element exist is updated. Therefore, the overall performance of the storage system can be improved.

First claim

We claim:

1. A method for managing a storage system, comprising:
receiving an access request for target data;
determining a storage position of the target data, the storage position indicating one of a storage device and a cache having a plurality of cache pages;
determining, based on the storage position, a target element corresponding to the target data contained in one of a first replacement list indicating recently accessed cache pages and a second replacement list indicating less recently accessed cache pages, the second replacement list associated with the first replacement list, the first replacement list including at least one counting element, at least one high-frequency access element indicating a corresponding cache page with a high access frequency in the cache, and at least one low-frequency access element indicating a corresponding cache page with a low access frequency in the cache, the counting element indicating an access count of data in the storage device, the second replacement list including at least one low-frequency access element, the low-frequency access element in the second replacement list indicating a corresponding cache page with a low access frequency in the cache; and
updating a position of the target element in the one of the first replacement list and the second replacement list containing the target element.

2. The method of claim 1 , wherein determining the storage position comprises:
looking up access information about the target data in the cache; and
determining, based on the access information, whether the target data exists on a cache page of the cache.

3. The method of claim 1 , wherein determining the target element corresponding to the target data comprises:
in response to determining that the storage position of the target data indicates the cache, determining that the target element is either the low-frequency access element in the second replacement list, the high-frequency access element in the first replacement list, or the low-frequency access element in the first replacement list.

4. The method of claim 1 , wherein determining the target element corresponding to the target data comprises:
in response to determining that the target data is absent from the cache, determining whether access information about the target data exists in the cache, the access information indicating an access count of the target data in the storage device;
in response to determining that the access information exists in the cache, determining from the access information, that the target element is a counting element corresponding to the access information and located in the first replacement list; and
in response to determining that the access information is absent from the cache, creating, as the target element, a counting element associated with the target data in the first replacement list.

5. The method of claim 4 , further comprising:
creating the access information about the target data in the cache, the access information indicating the access count of the target data in the storage device.

6. The method of claim 1 , wherein the target element is in the first replacement list and the target data exists in the cache, and wherein updating the position of the target element comprises:
determining whether the target element is either the low-frequency access element or the high-frequency access element contained in the first replacement list;
in response to the target element being the high-frequency access element in the first replacement list, setting the position of the target element as a start position of the first replacement list; and
in response to the target element being the low-frequency access element in the first replacement list, updating, based on an access interval of a cache page indicated by the target element, the position of the target element in the first replacement list.

7. The method of claim 6 , wherein updating the position of the target element in the first replacement list comprises:
obtaining a maximum value of access intervals of cache pages indicated by high-frequency access elements and low-frequency access elements in the first replacement list and the second replacement list respectively;
in response to the access interval exceeding the maximum value, setting the position of the target element as the start position of the first replacement list; and
in response to the access interval being less than the maximum value,
setting the target element from the low-frequency access element in the first replacement list to be the high-frequency access element in the first replacement list, and
setting the position of the target element as the start position of the first replacement list.

8. The method of claim 1 , wherein the target element is determined to be in the second replacement list and the target data is determined to exist on a cache page of the cache, and wherein updating the position of the target element comprises:
obtaining a maximum value of access intervals of cache pages indicated by high-frequency access elements and low-frequency access elements in the first replacement list and the second replacement list respectively;
in response to an access interval of a cache page indicated by the target element exceeding the maximum value, setting the position of the target element as a start position of the second replacement list; and
in response to the access interval being less than the maximum value, updating the position of the target element based on a first number, the first number indicating a total number of elements in the first replacement list.

9. The method of claim 8 , wherein updating the position of the target element comprises:
in response to the first number being less than a first predefined threshold, adding the target element from the second replacement list to a start position of the first replacement list.

10. The method of claim 8 , wherein updating the position of the target element comprises:
in response to the first number exceeding a first predefined threshold, moving a high-frequency access element or a low-frequency access element at an end position of the first replacement list to the second replacement list, the moved high-frequency access element being set as a low-frequency access element; and
adding the target element from the second replacement list to a start position of the first replacement list.

11. The method of claim 8 , further comprising:
determining whether an element at an end position of the first replacement list is a counting element; and
in response to determining the element is a counting element, removing the counting element from the first replacement list.

12. The method of claim 10 , wherein moving the high-frequency access element or the low-frequency access element at the end position of the first replacement list to the second replacement list comprises:
determining a second number, the second number indicating the number of elements in the second replacement list;
in response to the second number being less than a second predefined threshold, moving the high-frequency access element or the low-frequency access element at the end position of the first replacement list to the second replacement list; and
in response to the second number exceeding the second predefined threshold,
removing a low-frequency access element at an end position of the second replacement list; and
moving the high-frequency access element or the low-frequency access element at the end position of the first replacement list to the second replacement list.

13. The method of claim 1 , wherein responsive to determining that

Assignees

• Emc Ip Holding Co Llc

Inventors

• Xu Xinlei
• Yang Lifeng
• Gao Jian
• Dong Jibing
• Kang Jianbin
• Gao Hongpo

Classifications

• G06F12/122 Primary

  of the least frequently used [LFU] type, e.g. with individual count value · CPC title

• G06F12/0868

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

• G06F3/0629

  Configuration or reconfiguration of storage systems · CPC title

• G06F12/0871

  Allocation or management of cache space · CPC title

• G06F3/0689

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