De-Duplication Based Backup Of File Systems

• US 20120016839A1
• Filed: 07/14/2011
• Published: 01/19/2012
• Est. Priority Date: 07/15/2010
• Status: Active Grant

• Current Assignee: Delphix Corporation (Perforce Software Incorporated)
• Original Assignee: Delphix Corporation (Perforce Software Incorporated)
• Inventors: Yueh, Jedidiah
• Granted Patent: US 8,548,944 B2
• Time in Patent Office: Days
• US Class Current: 707/624
• CPC Class Codes: G06F 11/1435 using file system or storage system metadata
• CPC Class Codes: G06F 11/1453 using de-duplication of the data
• CPC Class Codes: G06F 16/128 Details of file system snapshots on the file-level, e.g. snapshot creation, administration, deletion use of snapshots for error detection or correction G06F11/14, G06F11/16
• CPC Class Codes: G06F 17/00 Digital computing or data processing equipment or methods, specially adapted for specific functions information retrieval, database structures or file system structures therefor G06F16/00
• CPC Class Codes: G06F 2201/84 Using snapshots, i.e. a logical point-in-time copy of the data
• CPC Class Codes: G06F 7/00 Methods or arrangements for processing data by operating upon the order or content of the data handled logic circuits H03K19/00

Abstract

File system backups are performed by copying information describing changes in the file system since a previous point in time. To restore data, a virtual restored file system (VRFS) structure is created corresponding to a snapshot of data copied from the file system that is stored in the backup file system. A client can read the data stored in the backup file system pointed at by the VRFS structure as well as write to the backup file system. Multiple clients can share blocks of data stored on the backup file system via the same VRFS structure or via multiple VRFS structures. If a client writes to a data block pointed at by a VRFS, a copy of the data block is made to which the client makes changes so that the data in the original data blocks is saved for other clients.

Claims

9-1. The method of claim 9, wherein one or more of the stored data blocks associated with the first set of files are also associated with the second set of files.

13. A method for performing backups of file systems, the method comprising:

receiving requests to perform backups of a plurality of source file systems, each request identifying a source file system;

for each request received, performing backup of an associated source file system, comprising;

receiving data blocks for a plurality of point-in-time copies of the associated source file system each point-in-time copy of the associated source file-system obtained by extracting data blocks from the associated source file-system that changed since a previous point-in-time copy was extracted, and

storing on a storage system, the data blocks; and

receiving a request to restore information obtained from a particular source file system, the request to restore identifying a target system; and

responsive to receiving the request to restore the particular source file system, creating a virtual restored file system, the creating comprising;

linking a set of files to a plurality of stored data blocks stored on the storage system, the data blocks associated with a plurality of point-in-time copies of the source file system and

mounting the set of files to the target system to allow the target system to access the set of files, the mounted set of files comprising the virtual restored file system.

14. The method of claim 13, further comprising:

sending a request to receive the data blocks for a point-in-time copy of the particular source file system.

15. The method of claim 13, wherein the plurality of stored data blocks linked to the set of files comprises at least a first stored data block received as part of a first point-in-time copy and a second stored data block received as part of a second point-in-time copy.

16. The method of claim 13, further comprising:

receiving a request to write data to the virtual restored file system;

identifying a stored data block from the plurality of stored data blocks; and

updating the stored data block based on the request to write.

17. The method of claim 13, wherein the request to restore information is a first request to restore information, the target system is a first target system, the set of files is a first set of files, the virtual restored file system is a first virtual restored file system, and the plurality of stored data blocks is a first plurality of stored data blocks, the method further comprising:

receiving a second request to restore information obtained from the particular source file system, the request identifying a second target system;

responsive to receiving the second request to restore, creating a second virtual restored file system, the creating comprising;

linking a second set of files to a second plurality of stored data blocks, and

mounting the second set of files to the second target system to allow the second target system to access the second set of files, the mounted second set of files comprising the second virtual restored file system.

18. The method of claim 17, wherein one or more of the stored data blocks associated with the first set of files are also associated with the second set of files.

19. The method of claim 17, further comprising:

receiving a request to write data to the first virtual restored file system;

identifying a stored data block from the first plurality of stored data blocks;

responsive to determining that the stored data block is associated with the second virtual restored file system, creating a copy of the stored data block and linking the first set of files to the copy of the stored data block; and

updating the copy of the stored data block based on the request to write.

20. The method of claim 13, wherein the request to restore is associated with a restore time point, wherein the plurality of stored data blocks comprise data blocks received as part of point-in-time copies extracted before the restore time.

21. A computer program product having a computer-readable storage medium storing computer-executable code for performing backup of file systems, the code comprising:

a block copy manager configured to;

receive data blocks for a plurality of point-in-time copies of a source file system, each point-in-time copy of the source file-system obtained by extracting data blocks from the source file-system that changed since a previous point-in-time copy was extracted;

a storage allocation manager module configured to;

store on a storage system, the data blocks;

a virtual restored file system manager configured to;

receive a request to restore information from the source file system for a target system; and

responsive to receiving the request to restore, create a virtual restored file system, the create comprising;

linking a set of files to a plurality of the data blocks stored on the storage system, the data blocks associated with a plurality of point-in-time copies of the source file system and

mounting the set of files to the target system to allow the target system to access the set of files, the mounted set of files comprising the virtual restored file system.