System and method for recovering file systems by restoring partitions

• US 9,026,499 B1
• Filed: 03/31/2011
• Issued: 05/05/2015
• Est. Priority Date: 03/31/2011
• Status: Active Grant

• Current Assignee: Emc IP Holding Company LLC (Dell Technologies Inc.)
• Original Assignee: EMC Corporation (Dell Technologies Inc.)
• Inventors: Rajimwale, Abhishek, Hsu, Windsor W.
• Primary Examiner(s): Pham, Khanh
• Assistant Examiner(s): HARPER, ELIYAH STONE
• Application Number:
  US13/077,726
• Time in Patent Office: 1,496 Days
• Field of Search: 707/620, 707/999.101, 707/999.102, 707/674
• US Class Current: 707/674
• CPC Class Codes: G06F 11/0727 in a storage system, e.g. in a DASD or network based storage system drivers for digital recording or reproducing units G06F3/06; circuits for error detection or correction within digital recording or reproducing units 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 11/14 Error detection or correction of the data by redundancy in operation G06F11/16 takes precedence
• CPC Class Codes: G06F 11/1453 using de-duplication of the data
• CPC Class Codes: G06F 11/1469 Backup restoration techniques
• CPC Class Codes: G06F 11/3476 Data logging G06F11/14, G06F11/2205 take precedence
• CPC Class Codes: G06F 16/288 Entity relationship models
• CPC Class Codes: G06F 16/972 Access to data in other repository systems, e.g. legacy data or dynamic Web page generation

Abstract

According to one embodiment, recovering file systems by restoring partitions is described. In one example, a method includes discovering an error in a storage partition of a file storage system, the storage partition including identification metadata to identify itself to the file system, finding a backup storage partition containing data and identification metadata corresponding to that of the error storage partition, restoring the error storage partition using the backup storage partition, and using the restored identification metadata to identify the restored storage partition to the file system.

Claims

1. A computer implemented method for recovering a file system, the method comprising:

discovering an error in a storage partition of a file storage system, the storage partition including identification metadata to identify itself to the file system, the error indicating that the storage partition having a portion of the file system that is not available, wherein the file storage system is a deduplicated file storage system that stores a reference to a previously stored data segment upon receiving a new data segment when the new data segment has already been stored in the file storage system;

finding a backup storage partition containing data and identification metadata corresponding to that of the error storage partition, wherein the backup storage partition is among a plurality of storage partitions to find the backup storage partition containing the data and identification metadata, wherein the identification metadata is used to identify backup storage partition corresponding to that of the error storage partition, and wherein the error storage partition and the backup storage partition can be individually shut down or powered up;

restoring the error storage partition using the backup storage partition; and

using the restored identification metadata to identify the restored storage partition to the file system.

2. The method of claim 1, further comprising, prior to discovering the error in the storage partition, making the found backup storage partition including writing identification metadata to the backup storage partition.

3. The method of claim 2, wherein the backup storage partition is located at a replica site having a second replica file storage system coupled to the file storage system through a network and wherein making the backup storage partition includes sending data to be written to the backup storage partition over the network to the replica file storage system.

4. The method of claim 1, further comprising setting an error value in a header of the error storage partition after discovering the error.

5. The method of claim 1, further comprising generating an alert and logging an error message identifying the error storage partition.

6. The method of claim 1, wherein restoring the error storage partition includes making a copy of the backup storage partition including the identification metadata and installing the copy in place of the error storage partition.

7. The method of claim 3, wherein the backup storage partition is located at a different backup or replica site and the copy of the backup storage partition is made at the backup or replica site.

8. The method of claim 7, further comprising transporting the copy of the backup storage partition from the backup or replica site to be installed in place of the error storage partition.

9. The method of claim 1, wherein the storage partition includes namespace metadata identifying files of the file storage system in the storage partition and in other storage partitions and wherein restoring the error partition includes restoring the namespace metadata.

10. A non-transitory computer-readable storage medium having instructions stored therein, which when executed by a computer, cause the computer to perform a method for configuring storage partitions of a file storage system, the method comprising:

selecting a storage partition as a target partition;

discovering an error in a storage partition of a file storage system, the storage partition including identification metadata to identify itself to the file system, and the error indicating that the storage partition having a portion of the file system that is not available, wherein the file storage system is a deduplicated file storage system that stores a reference to a previously stored data segment upon receiving a new data segment when the new data segment has already been stored in the file storage system;

finding a backup storage partition containing data and identification metadata corresponding to that of the error storage partition, wherein the backup storage partition is among a plurality of storage partitions to find the backup storage partition containing the data and identification metadata, wherein the identification metadata is used to identify backup storage partition corresponding to that of the error storage partition, and wherein the error storage partition and the backup storage partition can be individually shut down or powered up;

restoring the error storage partition using the backup storage partition; and

using the restored identification metadata to identify the restored storage partition to the file system.

11. The non-transitory computer-readable storage medium of claim 10, wherein the method further comprises setting an error value in a header of a respective partition after discovering an error.

12. The non-transitory computer-readable storage medium of claim 10, wherein the method further comprises reading an identifier of the error storage partition to determine if the error storage partition is an active storage partition and if the error storage partition is an active storage partition, then taking the active storage partition offline before replicating.

13. The non-transitory computer-readable storage medium of claim 10, wherein the backup storage partition is located at a different site and restoring the error storage partition is performed at the different site.

14. The non-transitory computer-readable storage medium of claim 13, wherein the error storage partition comprise a plurality of storage nodes grouped into a single logical entity to form a partition.

15. A storage system comprising;

a system memory;

a file system executed in the system memory, the file system having a plurality storage partitions, each storage partition including identification metadata to identify itself to the file system;

a partition manager coupled to the file system and the system memory, wherein the partition manager is configured to

discover an error in a storage partition of the file storage system, the error indicating that the storage partition having a portion of the file system that is not available,

find an external backup storage partition containing data corresponding to that of the error storage partition including the identification metadata, wherein the external storage partition is among a plurality of storage partitions to find the external backup storage partition containing the data, wherein the identification metadata is used to identify backup storage partition corresponding to that of the error storage partition, and wherein the error storage partition and the backup storage partition can be individually shut down or powered up; and

restore the error storage partition using the backup storage partition, wherein the storage system is a deduplicated storage system that stores a reference to a previously stored data segment upon receiving a new data segment when the new data segment has already been stored in the storage system.

16. The system of claim 15, wherein the partition manager is further configured to generate an alert and log an error message identifying the error storage partition.

17. The system of claim 15, wherein the backup storage partition is located at a different replica site and replicating restoring the error storage partition is performed at the different replica site.

18. The system of claim 17, wherein the partition manager is further configured to install the replicated backup storage partition using the identification metadata at the file storage system after it is received from the different site.

19. The system of claim 17, wherein the storage partition includes namespace metadata identifying files of the file storage system in the storage partition and in other storage partitions and wherein the partition manager in restoring the error partition restores the namespace metadata.