Block-based backups for sub-file modifications

• US 9,411,821 B1
• Filed: 03/27/2014
• Issued: 08/09/2016
• Est. Priority Date: 03/27/2014
• Status: Active Grant

• Current Assignee: Emc IP Holding Company LLC (Dell Technologies Inc.)
• Original Assignee: EMC Corporation (Dell Technologies Inc.)
• Inventors: Patwardhan, Kedar Shrikrishna, Multani, Suraj, Tadahal, Manjunath
• Primary Examiner(s): Nguyen, Cam-Linh
• Application Number:
  US14/227,202
• Time in Patent Office: 866 Days
• Field of Search: 707/639, 707/825
• US Class Current: 1/1
• CPC Class Codes: G06F 11/1435 using file system or storage system metadata
• CPC Class Codes: G06F 11/1446 Point-in-time backing up or restoration of persistent data
• CPC Class Codes: G06F 11/1451 by selection of backup contents
• CPC Class Codes: G06F 11/1453 using de-duplication of the data
• CPC Class Codes: G06F 11/1471 involving logging of persistent data for recovery
• 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 16/1865 Transactional file systems
• CPC Class Codes: G06F 2201/84 Using snapshots, i.e. a logical point-in-time copy of the data

Abstract

Block-based backups for sub-file modifications are described. A system records an identifier of a modified file into a file modification journal. The system records an identifier corresponding to a modified block in a file system into a modified block map. The system creates a modified file block map based on the identifier of the modified file in the file modification journal. The system identifies a modified file block corresponding to the modified file based on an intersection of the modified block map and the modified file block map. The system reads the modified file block from the file system using a file system read interface. The system writes the modified file block to a backup storage.

Claims

1. A system for block-based backups for sub-file modifications, the system comprising:

a processor-based application executed on a computer and configured to;

record an identifier of a modified file into a file modification journal;

record an identifier corresponding to a modified block in a file system into a modified block map;

create a modified file block map based on the identifier of the modified file in the file modification journal;

identify a modified file block corresponding to the modified file based on an intersection of the modified block map and the modified file block map;

read the modified file block from the file system using a file system read interface; and

write the modified file block to a backup storage.

2. The system of claim 1, wherein the processor-based application is further configured to:

create a backup copy of the modified file if the modified file is a newly created file;

delete the backup copy of the modified file if the modified file is a deleted file;

rename the backup copy of the modified file if the modified file is a renamed file; and

delete the modified file from the file modification journal if the modified file is one of the newly created file, the deleted file, and the renamed file.

3. The system of claim 1, wherein the processor-based application is further configured to delete the modified file from the file modification journal if the modified file is a user-specified file type.

4. The system of claim 1, wherein creating the modified file block map comprises using an application program interface associated with the file system to query the file system based on the modified file.

5. The system of claim 1, wherein the modified file block map comprises a mapping of a logical offset corresponding to the modified file to a corresponding physical location of a corresponding block that contains data corresponding to the logical offset.

6. The system of claim 1, wherein identifying the modified file block comprises identifying a logical offset and a length of consecutive modified blocks corresponding to the modified file.

7. The system of claim 1, wherein writing the modified file block to the backup storage comprises:

creating a mounted backup image by mounting a previously created block-based backup of the file system onto a proxy host;

enabling a forward snapshot of the mounted backup image; and

creating a forward snapshot file for the modified file by writing the modified file block to the mounted backup image using a file system write interface.

8. A computer-implemented method for block-based backups for sub-file modifications, the method comprising:

recording an identifier of a modified file into a file modification journal;

recording an identifier corresponding to a modified block in a file system into a modified block map;

creating a modified file block map based on the identifier of the modified file in the file modification journal;

identifying a modified file block corresponding to the modified file based on an intersection of the modified block map and the modified file block map;

reading the modified file block from the file system using a file system read interface; and

writing the modified file block to a backup storage.

9. The method of claim 8, wherein the method further comprises:

creating a backup copy of the modified file if the modified file is a newly created file;

deleting the backup copy of the modified file if the modified file is a deleted file;

renaming the backup copy of the modified file if the modified file is a renamed file; and

deleting the modified file from the file modification journal if the modified file is one of the newly created file, the deleted file, the renamed file, and a user-specified file type.

10. The method of claim 8, wherein creating the modified file block map comprises using an application program interface associated with the file system to query the file system based on the modified file.

11. The method of claim 8, wherein the modified file block map comprises a mapping of a logical offset corresponding to the modified file to a corresponding physical location of a corresponding block that contains data corresponding to the logical offset.

12. The method of claim 8, wherein identifying the modified file block comprises identifying a logical offset and a length of consecutive modified blocks corresponding to the modified file.

13. The method of claim 8, wherein writing the modified file block to the backup storage comprises:

creating a mounted backup image by mounting a previously created block-based backup of the file system onto a proxy host;

enabling a forward snapshot of the mounted backup image; and

creating a forward snapshot file for the modified file by writing the modified file block to the mounted backup image using a file system write interface.

14. A computer program product, comprising a non-transitory computer-readable medium having a computer-readable program code embodied therein to be executed by one or more processors, the program code including instructions to:

record an identifier of a modified file into a file modification journal;

record an identifier corresponding to a modified block in a file system into a modified block map;

create a modified file block map based on the identifier of the modified file in the file modification journal;

identify a modified file block corresponding to the modified file based on an intersection of the modified block map and the modified file block map;

read the modified file block from the file system using a file system read interface; and

write the modified file block to a backup storage.

15. The computer program product of claim 14, wherein the program code includes further instructions to:

create a backup copy of the modified file if the modified file is a newly created file;

delete the backup copy of the modified file if the modified file is a deleted file;

rename the backup copy of the modified file if the modified file is a renamed file; and

delete the modified file from the file modification journal if the modified file is one of the newly created file, the deleted file, and the renamed file.

16. The computer program product of claim 14, wherein the program code includes further instructions to delete the modified file from the file modification journal if the modified file is a user-specified file type.

17. The computer program product of claim 14, wherein creating the modified file block map comprises using an application program interface associated with the file system to query the file system based on the modified file.

18. The computer program product of claim 14, wherein the modified file block map comprises a mapping of a logical offset corresponding to the modified file to a corresponding physical location of a corresponding block that contains data corresponding to the logical offset.

19. The computer program product of claim 14, wherein identifying the modified file block comprises identifying a logical offset and a length of consecutive modified blocks corresponding to the modified file.

20. The computer program product of claim 14, wherein writing the modified file block to the backup storage comprises:

creating a mounted backup image by mounting a previously created block-based backup of the file system onto a proxy host;

enabling a forward snapshot of the mounted backup image; and

creating a forward snapshot file for the modified file by writing the modified file block to the mounted backup image using a file system write interface.