SYSTEM AND METHOD FOR INFORMATION HANDLING SYSTEM REDUNDANT STORAGE REBUILD

• US 20120079317A1
• Filed: 09/27/2010
• Published: 03/29/2012
• Est. Priority Date: 09/27/2010
• Status: Active Grant

• Current Assignee: Dell Products LP (Dell Technologies Inc.)
• Original Assignee: Dell Products LP (Dell Technologies Inc.)
• Inventors: Nelogal, Chandrashekar, Yu, Frank Widjaja, Le, Bang Kim
• Granted Patent: US 8,726,070 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 2211/1035 Keeping track, i.e. keeping track of data and parity changes

Abstract

Out-of-order reconstruction of a RAID storage device at a replacement storage device enables the replacement storage device to execute I/O for reconstructed regions during reconstruction of the replacement storage device. In one embodiment, the failed storage device is analyzed to find recoverable information, which is copied to the replacement storage device to reduce the need for reconstruction. In another embodiment, the priority for region'"'"'s reconstruction is increased upon detection of an I/O to the region. The I/O is queued until reconstruction of the region and then executed after reconstruction of that region so that I/O at the region need not be repeated during reconstruction of the remainder of the replacement storage device.

Claims

1. A method for rebuilding a first storage device of a RAID array at a replacement storage device, the RAID array having plural storage devices, the method comprising:

determining a failure of the first storage device;

analyzing the failure to detect at least some recoverable information associated with the first storage device; and

copying the recoverable information from the first storage device to the replacement storage device.

2. The method of claim 1 further comprising:

determining non-recoverable information associated with the first storage device; and

performing a parity operation to re-create the non-recoverable information on the replacement storage device from the RAID array plural storage devices.

3. The method of claim 1 wherein the first storage device comprises a hard disk drive having plural memory components and the failure comprises failure of less than all the memory components.

4. The method of claim 3 wherein copying further comprises copying information from non-failed memory components to the replacement storage device.

5. The method of claim 1 wherein the failure comprises a failure of an ability to write information to the first storage device.

6. The method of claim 5 wherein copying further comprises:

copying information from the first storage device to the replacement storage device; and

updating the replacement storage device with writes of data directed to the first storage device after the failure to write information.

7. The method of claim 1 further comprising:

determining non-recoverable information associated with the first storage device;

detecting an I/O command for writing to a portion of the non-recoverable information;

queuing the I/O command;

prioritizing re-creation of the portion at the replacement storage device; and

performing the queued I/O command at the replacement storage device after the portion is re-created.

8. The method of claim 1 wherein the plural storage devices comprise hard disk drives.

9. A method for reconstructing a first storage device of a RAID array at a replacement storage device, the RAID array having plural storage devices, the method comprising:

detecting an I/O to a first region of the first storage device;

increasing the priority of reconstruction of the first region at the replacement storage device; and

performing the I/O at the first region of the replacement storage device after completion of the reconstruction of the first region at the replacement storage device.

10. The method of claim 9 wherein the I/O comprises a write of information to the first region.

11. The method of claim 9 wherein increasing the priority further comprises:

creating a queue of I/O to the first storage device, the queue having the order in which the I/O are received, each I/O associated with a region of the first storage device; and

reconstructing the first storage device at the replacement storage device in the order of the queue.

12. The method of claim 11 further comprising:

determining that the queue is empty; and

reconstructing the first storage device at the replacement storage device in a sequential order of regions.

13. The method of claim 9 further comprising:

determining that the first region has been reconstructed at the time of the I/O; and

executing the I/O based upon the determining.

14. The method of claim 9 further comprising reconstructing the first region with a parity operation.

15. The method of claim 9 further comprising:

reconstructing the first storage device at the replacement storage device in a non-sequential order based at least in part upon the priority.

16. An information handling system comprising:

plural components operable to process information;

plural storage devices operable to store the information;

a RAID controller interfaced with the plural storage devices to coordinate storage of the information at the storage devices as an array having redundancy;

a reconstruction module interfaced with the RAID controller and operable to reconstruct information stored on a first of the plural storage devices onto a replacement storage device, the reconstruction module reconstructing the first storage device in a predetermined order using a rebuild operation; and

a priority module interfaced with the reconstruction module and operable to adjust the predetermined order based upon one or more predetermined factors.

17. The information handling system of claim 16 wherein the predetermined factors comprise recoverable information on the first storage device, the priority module reconstructing the first storage device on the replacement storage device by copying the recoverable information from the first storage device to the second storage device before reconstructing other information with the rebuild operation.

18. The information handling system of claim 16 wherein the predetermined factors comprise detection of an I/O directed to the first storage device, the priority module increasing the priority for reconstruction of a region of the first storage device that is associated with the I/O.

19. The information handling system of claim 18 further comprising a priority table populated with I/O directed to the first storage region and an order of receipt of the I/O, the priority module operable to reconstruct the first storage device at the replacement storage device according to the order of receipt of the I/O.

20. The information handling system of claim 16 wherein the priority module is further operable to determine if reconstruction has occurred in a region of the replacement storage device and to allow writes to the region during reconstruction of the replacement storage device.