Systems and methods for wear levelling in a storage array

• US 10,656,843 B2
• Filed: 05/16/2016
• Issued: 05/19/2020
• Est. Priority Date: 05/16/2016
• Status: Active Grant

• Current Assignee: Dell Products LP (Dell Technologies Inc.)
• Original Assignee: Dell Products LP (Dell Technologies Inc.)
• Inventors: B, Kanaka Charyulu
• Primary Examiner(s): Khan, Masud K
• Application Number:
  US15/155,678
• Publication Number:
  US 20170329536A1
• Time in Patent Office: 1,464 Days
• Field of Search: None
• CPC Class Codes: G06F 12/02 Addressing or allocation; Relocation program address sequencing G06F9/00; arrangements for selecting an address in a digital store G11C8/00
• CPC Class Codes: G06F 13/42 Bus transfer protocol, e.g. handshake; Synchronisation
• CPC Class Codes: G06F 3/061 Improving I/O performance
• CPC Class Codes: G06F 3/0616 in relation to life time, e.g. increasing Mean Time Between Failures [MTBF]
• CPC Class Codes: G06F 3/0617 in relation to availability
• CPC Class Codes: G06F 3/0631 by allocating resources to storage systems
• CPC Class Codes: G06F 3/0664 at device level, e.g. emulation of a storage device or system
• CPC Class Codes: G06F 3/0689 Disk arrays, e.g. RAID, JBOD
• CPC Class Codes: G06F 9/50 Allocation of resources, e.g. of the central processing unit [CPU]
• CPC Class Codes: G06F 9/5016 the resource being the memory

Abstract

In accordance with embodiments of the present disclosure, a system may include a processor and a storage interface configured to sequentially select, one at a time, member storage resources of a virtual storage resource as a source storage resource for redirection of write input/output (I/O) and for each member storage resource, when selected as the source storage resource, in response to write I/O, redirect the write I/O to a spare storage resource available to the virtual storage resource.

Claims

1. A system comprising:

at least one processor; and

a storage interface configured to;

sequentially select member storage resources of a virtual storage resource as a source storage resource for redirection of write input/output (I/O);

for each member storage resource, when selected as the source storage resource, change a configuration of the virtual storage resource from an original configuration to a redirect configuration by, in response to write I/O, redirecting the write I/O from a first address of the source storage resource to a second address of a spare storage resource available to the virtual storage resource, wherein the spare storage resource is a hot spare storage resource of the virtual storage resource;

maintain a redirect mapping table of respective first addresses and corresponding second addresses;

in response to a detection that a copy back condition has occurred, initiate a copy back operation configured to return the virtual storage resource to the original configuration, wherein the copy back condition comprises a wear level of the spare storage resource and/or an I/O level of the spare storage resource; and

maintain a copy back mapping table indicative of data of the source storage resource which is not to be overwritten during the copy back operation.

2. The system of claim 1, the storage resource further configured to, responsive to the detection of the copy back condition, copy back data associated with the write I/O redirected to the spare storage resource from the spare storage resource to the source storage resource.

3. The system of claim 2, wherein the storage resource is configured to copy back only data associated with the write I/O redirected to the spare storage resource and unmodified by write I/O directed to the source storage resource occurring after occurrence of the copy back condition.

4. The system of claim 2, wherein the copy back condition further comprises a passage of a duration of time since a previous copy back of data from the spare storage resource to a member storage resource.

5. The system of claim 4, wherein the duration of time is based on a wear level of at least one of:

the spare storage resource; and

one of the member storage resources.

6. The system of claim 2, wherein the storage interface is configured to, in response to read I/O associated with particular data of the source storage resource, redirect the read I/O to the spare storage resource if the particular data was associated with a write I/O redirected to the spare storage resource and unmodified by write I/O directed to the source storage resource occurring after occurrence of the condition.

7. The system of claim 1, the storage resource further configured to, for each member storage resource, when selected as the source storage resource, redirect the write I/O to the spare storage resource responsive to occurrence of a condition for redirecting write I/O.

8. The system of claim 7, wherein the condition for redirecting further comprises one of:

a passage of a duration of time since a previous redirection of data from a member storage resource to the spare storage resource;

a wear level of the source storage resource attaining a particular threshold; and

an I/O level of the source storage resource attaining a particular threshold.

9. The system of claim 1, wherein the storage interface is configured to, in response to read I/O associated with particular data of the source storage resource, redirect the read I/O to the spare storage resource if the particular data was associated with a write I/O redirected to the spare storage resource.

10. The system of claim 1, wherein the storage interface is configured such that no data other than the redirected write I/O is written from the source storage resource to the spare storage resource.

11. A method comprising:

sequentially selecting member storage resources of a virtual storage resource as a source storage resource for redirection of write input/output (I/O);

for each member storage resource, when selected as the source storage resource, change a configuration of the virtual storage resource from an original configuration to a redirect configuration by, in response to write I/O, redirecting the write I/O from a first address of the source storage resource to a second address of a spare storage resource available to the virtual storage resource, wherein the spare storage resource is a hot spare storage resource of the virtual storage resource;

maintaining a redirect mapping table of respective first addresses and corresponding second addresses;

in response to a detection that a copy back condition has occurred, initiating a copy back operation configured to return the virtual storage resource to the original configuration, wherein the copy back condition comprises a wear level of the spare storage resource and/or an I/O level of the spare storage resource; and

maintaining a copy back mapping table indicative of data of the source storage resource which is not to be overwritten during the copy back operation.

12. The method of claim 11, further comprising, responsive to the detection of the copy back condition, copying back data associated with the write I/O redirected to the spare storage resource from the spare storage resource to the source storage resource.

13. The method of claim 12, further comprising copying back only data associated with the write I/O redirected to the spare storage resource and unmodified by write I/O directed to the source storage resource occurring after occurrence of the copy back condition.

14. The method of claim 12, wherein the copy back condition further comprises a passage of a duration of time since a previous copy back of data from the spare storage resource to a member storage resource.

15. The method of claim 14, wherein the duration of time is based on a wear level of at least one of:

the spare storage resource; and

one of the member storage resources.

16. The method of claim 12, further comprising, in response to read I/O associated with particular data of the source storage resource, redirecting the read I/O to the spare storage resource if the particular data was associated with a write I/O redirected to the spare storage resource and unmodified by write I/O directed to the source storage resource occurring after occurrence of the condition.

17. The method of claim 11, further comprising, for each member storage resource, when selected as the source storage resource, redirecting the write I/O to the spare storage resource responsive to occurrence of a condition for redirecting write I/O.

18. The method of claim 17, wherein the condition for redirecting further comprises one of:

a passage of a duration of time since a previous redirection of data from a member storage resource to the spare storage resource;

a wear level of the source storage resource attaining a particular threshold; and

an I/O level of the source storage resource attaining a particular threshold.

19. The method of claim 11, further comprising, in response to read I/O associated with particular data of the source storage resource, redirecting the read I/O to the spare storage resource if the particular data was associated with a write I/O redirected to the spare storage resource.

20. The method of claim 11, wherein no data other than the redirected write I/O is written from the source storage resource to the spare storage resource.

21. An article of manufacture comprising:

a non-transitory computer readable medium; and

computer-executable instructions carried on the computer readable medium, the instructions readable by at least one processor, the instructions, when read and executed, for causing the at least one processor to;

sequentially select member storage resources of a virtual storage resource as a source storage resource for redirection of write input/output (I/O);

for each member storage resource, when selected as the source storage resource, change a configuration of the virtual storage resource from an original configuration to a redirect configuration by, in response to write I/O, redirecting the write I/O from a first address of the source storage resource to a second address of a spare storage resource available to the virtual storage resource, wherein the spare storage resource is a hot spare storage resource of the virtual storage resource;

maintain a redirect mapping table of respective first addresses and corresponding second addresses;

in response to a detection that a copy back condition has occurred, initiate a copy back operation configured to return the virtual storage resource to the original configuration, wherein the copy back condition comprises a wear level of the spare storage resource and/or an I/O level of the spare storage resource; and

maintain a copy back mapping table indicative of data of the source storage resource which is not to be overwritten during the copy back operation.