Storage control apparatus and method

• US 20060212748A1
• Filed: 09/29/2005
• Published: 09/21/2006
• Est. Priority Date: 03/15/2005
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Konta, Yoshihito, Kubota, Norihide, Ito, Mikio, Takahashi, Hideo, Ikeuchi, Kazuhiko, Daikokuya, Hidejiro, Makino, Tsukasa, Ochi, Hiroaki, Mochizuki, Shinya, Sato, Yasutake
• Granted Patent: US 7,809,979 B2
• Time in Patent Office: Days
• US Class Current: 714/6
• CPC Class Codes: G06F 11/1092 Rebuilding, e.g. when physically replacing a failing disk
• CPC Class Codes: G06F 2211/1035 Keeping track, i.e. keeping track of data and parity changes

Abstract

In a system for dispersively storing data and parity in a plurality of storage devices, information in a first storage device is restored by using information stored in the storage devices other than the first storage device when the first storage device fails. And information in a non-restored area in the first storage device and information in a second storage device are restored by using information stored in the storage devices other than the first and the second storage devices when the second storage device fails while the information in the first storage device is being restored.

Claims

1. A storage control apparatus for realizing a redundancy of data by conducting a control by which data and parity are dispersively stored in a plurality of storage devices, comprising:

a first rebuild device for restoring information in a first storage device by using information stored in the storage devices other than the first storage device, and writing the restored information in a first spare storage device, when the first storage device among the plurality of the storage devices fails; and

a second rebuild device for restoring information in a non-restored area in the first storage device and information in a second storage device by using information stored in the storage devices other than the first and the second storage devices, and respectively writing the restored information in a corresponding area in the first spare storage device and in a second spare storage device, when the second storage device fails while the information in the first storage device is being restored.

2. The storage control apparatus according to claim 1, wherein:

the second rebuild device respectively executes a process for restoring information in the non-restored area in the first storage device and a process for restoring information in the second storage device independently and parallelly.

3. The storage control apparatus according to claim 1, wherein:

the second rebuild device restores information in a corresponding area in the second storage device by using information in an area corresponding to the restored area in the first storage device stored in the storage devices other than the first and the second storage devices, and thereafter, restores information in the non-restored area in the first storage device and information in the corresponding area in the second storage device by using information in an area corresponding to the non-restored area in the first storage device stored in the storage devices other than the first and the second storage devices.

4. The storage control apparatus according to claim 1, wherein:

the second rebuild device compares, with a threshold value, a difference between a restoration progress position in the first storage device and a restoration progress position in the second storage device, and respectively executes a process for restoring information in the non-restored area in the first storage device and a process for restoring information in the second storage device independently and parallelly when the difference between the restoration progress positions is equal to or greater than the threshold value, and restores information in a corresponding area in the second storage device by using information in an area corresponding to the restored area in the first storage device stored in the storage devices other than the first and the second storage devices, and thereafter, restores information in the non-restored area in the first storage device and information in the corresponding area in the second storage device by using information in an area corresponding to the restored area in the first storage device stored in the storage devices other than the first and the second storage devices when the difference between the restoration progress positions is smaller than the threshold value.

5. The storage control apparatus according to claim 1, wherein:

the second rebuild device restores information in the non-restored area in the first storage device and information in the corresponding area in the second storage device by using information in the area corresponding to the non-restored area in the first storage device stored in the storage devices other than the first and the second storage devices, and thereafter, restores information in the corresponding area in the second storage device by using information in the area corresponding to the restored area in the first storage device stored in the storage devices other than the first and the second storage devices.

6. The storage control apparatus according to claim 1, wherein:

the second rebuild device parallelly executes a process for restoring information in the corresponding area in the second storage device by using information in the area corresponding to the restored area in the first storage device stored in the storage devices other than the first and the second storage devices, and a process for restoring information in the non-restored area in the first storage device and information in the corresponding area in the second storage device by using information in the area corresponding to the non-restored area in the first storage device stored in the storage devices other than the first and the second storage devices.

7. The storage control apparatus according to one of claim 1 to claim 6, further comprising:

a holding device for holding bitmap information which indicates whether or not an area in the first and the second storage devices is restored for each prescribed area, wherein;

the second rebuild device restores information in areas other than the restored area by referring to the bitmap information.

8. The storage control apparatus according to claim 7, wherein:

the second rebuild device restores information as an access target, and records, in the position corresponding to the information as the access target in the bitmap information, the information indicating that the corresponding area is restored, when an access request to the first or the second storage devices occurs.

9. A storage apparatus, comprising:

a plurality of storage devices for dispersively storing data and parity for realizing a redundancy of data;

a first rebuild device for restoring information in a first storage device by using information stored in the storage devices other than the first storage device, and writing the restored information in a first spare storage device, when the first storage device among the plurality of the storage devices fails; and

a second rebuild device for restoring information in a non-restored area in the first storage device and information in a second storage device by using information stored in the storage devices other than the first and the second storage devices, and respectively writing the restored information in a corresponding area in the first spare storage device and in a second spare storage device, when the second storage device fails while the information in the first storage device is being restored.

10. A computer readable recording medium which records a program for a processor realizing a redundancy of data by conducting a control by which data and parity are dispersively stored in a plurality of storage devices, causing the processor to execute:

a process of restoring information in a first storage device by using information stored in the storage devices other than the first storage device, and writing the restored in formation in a first spares to rage device, when the first storage device among the plurality of the storage devices fails; and

a process of restoring information in a non-restored area in the first storage device and information in a second storage device by using information stored in storage devices other than the first and the second storage devices, and respectively writing the restored information in a corresponding area in the first spare storage device and in a second spare storage device,

when the second storage device fails while the information in the first storage device is being restored.