PERFORMANCE ENHANCEMENT TECHNIQUE FOR RAIDS UNDER REBUILD

• US 20130073900A1
• Filed: 09/20/2011
• Published: 03/21/2013
• Est. Priority Date: 09/20/2011
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Li, Chao Guang, Song, Cheng-Chung, Zhang, Hui, Peng, Yao, Wang, Zhi Qiang
• Granted Patent: US 8,719,619 B2
• Time in Patent Office: Days
• US Class Current: 714/6.22
• CPC Class Codes: G06F 11/1092 Rebuilding, e.g. when physically replacing a failing disk
• CPC Class Codes: G06F 11/3034 where the computing system component is a storage system, e.g. DASD based or network based digital input from or digital output to record carriers G06F3/06; digital recording or reproducing G11B20/18; for distributed storage of data in networks, e.g. transport arrangements for network file system [NFS], storage area networks [SAN] or network attached storage [NAS], H04L67/1097
• CPC Class Codes: G06F 11/3055 Monitoring arrangements for monitoring the status of the computing system or of the computing system component, e.g. monitoring if the computing system is on, off, available, not available error or fault processing without redundancy G06F11/0703; error detection or correction by redundancy in data representation G06F11/08; error detection or correction by redundancy in operation G06F11/14; error detection or correction by redundancy in hardware G06F11/16
• CPC Class Codes: G06F 11/3409 for performance assessment

Abstract

A method for improving the performance of a RAID under rebuild is disclosed. In one embodiment, such a method includes identifying a RAID requiring rebuild, such as by identifying a RAID having one or more failed storage-drive components. The method then automatically performs the following in response to identifying the RAID: the method identifies hot extents (i.e., extents most heavily accessed) in the RAID; the method migrates the hot extents from the identified failed RAID to a normal RAID not requiring rebuild, such as to an underused RAID; and the method rebuilds the failed RAID. The migration of the hot extents will ideally occur while the RAID is being rebuilt but may also be performed prior to the rebuild process. A corresponding apparatus and computer program product are also disclosed.

Claims

1. A method for improving the performance of a RAID under rebuild, the method comprising:

identifying a RAID requiring rebuild;

automatically performing the following in response to identifying the RAID;

identifying hot extents on the RAID, the hot extents comprising the most heavily accessed extents on the RAID;

migrating the hot extents from the RAID to a normal RAID not requiring rebuild; and

rebuilding the RAID.

2. The method of claim 1, wherein migrating the hot extents comprises migrating the hot extents while rebuilding the RAID.

3. The method of claim 1, wherein migrating the hot extents comprises migrating the hot extents prior to rebuilding the RAID.

4. The method of claim 1, wherein identifying the hot extents comprises analyzing historical usage data to identify the hot extents.

5. The method of claim 1, wherein migrating the hot extents comprises migrating about 10 to 30 percent of the extents on the RAID to the normal RAID.

6. The method of claim 5, wherein migrating the hot extents comprises migrating about 20 percent of the extents on the RAID to the normal RAID.

7. The method of claim 1, wherein the normal RAID is an underused normal RAID.

8. The method of claim 1, wherein migrating the hot extents comprises migrating up to a specified number of hot extents.

9. A computer program product for improving the performance of a RAID under rebuild, the computer program product comprising a non-transitory computer-readable storage medium having computer-usable program code embodied therein, the computer-usable program code comprising:

computer-usable program code to identify a RAID requiring rebuild; and

computer-usable program code to automatically perform the following in response to identifying the RAID;

identify hot extents on the RAID, the hot extents comprising the most heavily accessed extents on the RAID;

migrate the hot extents from the RAID to a normal RAID not requiring rebuild; and

rebuild the RAID.

10. The computer program product of claim 9, wherein migrating the hot extents comprises migrating the hot extents while rebuilding the RAID.

11. The computer program product of claim 9, wherein migrating the hot extents comprises migrating the hot extents prior to rebuilding the RAID.

12. The computer program product of claim 9, wherein identifying the hot extents comprises analyzing historical usage data to identify the hot extents.

13. The computer program product of claim 9, wherein migrating the hot extents comprises migrating about 10 to 30 percent of the extents of the RAID to the normal RAID.

14. The computer program product of claim 13, wherein migrating the hot extents comprises migrating about 20 percent of the extents of the RAID to the normal RAID.

15. The computer program product of claim 9, wherein the normal RAID is an underused normal RAID.

16. The computer program product of claim 9, wherein migrating the hot extents comprises migrating up to a specified number of hot extents.

17. An apparatus for improving the performance of a RAID under rebuild, the apparatus comprising:

at least one processor;

at least one memory device coupled to the at least processor and storing computer instructions for execution on the at least one processor, the computer instructions causing the at least one processor to collectively;

identify a RAID requiring rebuild;

identify hot extents on the RAID, the hot extents comprising the most heavily accessed extents on the RAID;

migrate the hot extents from the RAID to a normal RAID not requiring rebuild; and

rebuild the RAID.

18. The apparatus of claim 17, wherein migrating the hot extents comprises migrating the hot extents while rebuilding the RAID.

19. The apparatus of claim 17, wherein migrating the hot extents comprises migrating the hot extents prior to rebuilding the RAID.

20. The apparatus of claim 17, wherein migrating the hot extents comprises migrating about 10 to 30 percent of the extents of the RAID to the normal RAID.