Enhanced storage device replacement system and method

• US 8,650,435 B2
• Filed: 06/08/2011
• Issued: 02/11/2014
• Est. Priority Date: 06/08/2011
• Status: Active Grant

• Current Assignee: Dell Products LP (Dell Technologies Inc.)
• Original Assignee: Dell Products LP (Dell Technologies Inc.)
• Inventors: Vishnu, Murty K., Deepu, Syam Sreedhar M., Nagendra, A. S., Sandeep, Agarwal, Vaibhav, Kumar
• Primary Examiner(s): Ehne, Charles
• Application Number:
  US13/155,554
• Publication Number:
  US 20120317439A1
• Time in Patent Office: 979 Days
• Field of Search: 714/6.1, 714/6.2, 714/6.21, 714/6.22
• US Class Current: 714/6.1
• CPC Class Codes: G06F 11/1092 Rebuilding, e.g. when physically replacing a failing disk
• CPC Class Codes: G06F 11/2094 Redundant storage or storage space G06F11/2056 takes precedence

Abstract

Recovery of a failed storage device of a RAID array to a replacement storage device is improved by initiating recovery before failure of the storage device occurs. If failure occurs before completing the transfer of all information from the failed storage device to the replacement storage device, then the RAID controller identifies untransferred information to recreate the failed storage device at the replacement storage device by re-building only the untransferred information with a parity operation using information stored at the array.

Claims

1. A method for re-building information stored on a source storage device at a replacement storage device, the method comprising:

copying some but not all of the information from the source storage device to the replacement storage device, the information stored in plural stripes, the copying performed one stripe at a time;

tracking completion of the copying of each stripe;

detecting a failure at the source storage device;

retaining at the replacement storage device the information copied from the source storage device;

retrieving from one or more secondary source storage devices to the replacement storage device the stripes needed to complete re-building the source storage device at the replacement storage device.

2. The method of claim 1 wherein the storage device comprises a hard disk drive.

3. The method of claim 1 wherein the secondary source storage devices comprise plural storage devices disposed in a storage array with the source storage device.

4. The method of claim 1 wherein copying some but not all of the information further comprises:

predicting a failure of the source storage device;

in response to the predicting, initiating the copying of the information from the source storage device to the replacement storage device; and

failing at the source storage device before copying all information at the source storage device to the replacement storage device.

5. The method of claim 1 wherein copying some but not all of the information further comprises:

copying a stripe from the source storage device to the replacement storage device; and

incrementing sequentially to a next stripe to copy from the source storage device to the replacement storage device.

6. The method of claim 5 wherein detecting a failure further comprises storing a check point of the stripe last copied to the replacement storage device.

7. The method of claim 6 wherein retrieving from one or more secondary source storage devices to the replacement storage device the information needed to complete re-building the source storage device at the replacement storage device further comprises retrieving stripes from secondary storage devices of an array of storage devices, the stripes retrieved with a parity operation.

8. The method of claim 7 wherein the array comprises a RAID-5 array of plural storage devices.

9. An information handling system comprising:

a processor operable to execute instructions;

plural storage devices interfaced with the processor and operable to store information, including a source storage device, a replacement storage device, and one or more secondary source storage devices; and

memory interfaced with the processor and storing instructions operable to;

initiate transfer of all information stored at a source storage device to a replacement storage device, the information organized as stripes;

tracking completion of transfer of information by completion of transfer of each stripe;

detect failure of the source storage device after a transferred portion of the information is copied to the replacement storage device and before an untransferred portion is copied to the replacement storage device; and

retrieve, in response to the failure, the untransferred portion from the one or more secondary storage devices to copy the untransferred portion to the replacement storage device, the untransferred portion identified as stripes that did not complete transfer.

10. The information handling system of claim 9 wherein the processor comprises a RAID controller.

11. The information handling system of claim 10 wherein the RAID controller executes as a RAID 5 storage array.

12. The information handling system of claim 10 wherein the storage devices comprise hard disk drives.

13. The information handling system of claim 10 wherein the storage devices comprise solid state drives.

14. The information handling system of claim 9 wherein the instructions are further operable to predict a failure of the source storage device and to automatically initiate transfer of information to the replacements storage device in response to the detecting.

15. The information handling system of claim 9 wherein the instructions are further operable to track the transferred portion by incrementally copying stripes from the source storage device to the replacement storage device.

16. The information handling system of claim 15 wherein the instructions are further operable to copy the untransferred portion with a parity operation.

17. A method for storing information in an array having plural storage devices, the array organizing the information as plural stripes at each of the plural storage devices, the method comprising:

predicting failure of a first of the storage devices;

in response to the predicting, initiating transfer of the information from the first storage device to a second storage device by incrementing through the stripes of the first storage device to copy each striped to the second storage device;

detecting failure of a stripe to copy from the first storage device without detecting failure of the first storage device;

in response to detecting failure of a stripe to copy, rebuilding the stripe that failed to copy with a parity operation from the array and then continuing with the incrementing;

detecting failure of the first storage device before completing the transfer of the information to the second storage device;

identifying untransferred information that was not copied from the first storage device to the second storage device before the failure by identifying stripes that did not transfer from the first storage device to the second storage device; and

retrieving the untransferred information from the array to the second storage device.

18. The method of claim 17 wherein the storage devices comprise a RAID array managed by a RAID controller.

19. The method of claim 17 wherein the identifying untransferred information further comprises tracking stripes of the information with a checkpoint as each stripe is completely copied from the first storage device to the second storage device.

20. The method of claim 19 wherein retrieving the untransferred information further comprises retrieving untransferred stripes using a parity operation.