System and method for providing data protection by using sparse files to represent images of data stored in block devices

• US 7,831,639 B1
• Filed: 12/22/2004
• Issued: 11/09/2010
• Est. Priority Date: 12/22/2004
• Status: Expired due to Fees

• Current Assignee: Veritas Technologies, LLC (Whitehouse Group Ltd.)
• Original Assignee: Symantec Operating Corporation (NortonLifeLock Inc.)
• Inventors: Colgrove, John A., Panchbudhe, Ankur P., Kekre, Anand A.
• Primary Examiner(s): Stevens; Robert
• Application Number:
  US11/020,862
• Time in Patent Office: 2,148 Days
• Field of Search: 707/100, 707/203, 707/204, 707/816, 707/999.206, 715/721, 711/151, 711/170
• US Class Current: 707/816
• CPC Class Codes: G06F 16/10 File systems; File servers

Abstract

Various systems and methods are disclosed for storing one or more point-in-time images of data stored in a block device in a sparse file. In one embodiment, a method involves identifying a block of data within a block device and copying the block of data to a sparse file. The block of data is identified in response to being modified. The sparse file stores an incremental image of data stored in the block device. In addition to storing an incremental image, sparse files can be used to store full images. Furthermore, a sparse file can store multiple images (full and/or incremental) of data stored in a block device.

Claims

1. A method comprising:

creating a first point-in-time image of a volume in a sparse file, wherein

the first point-in-time image is represented in a sparse format, and

the creating the first point-in-time image comprises;

identifying a first block of data within the volume, wherein

the first block of data is identified in response to being modified subsequent to a particular point in time, and

storing a copy of the first block of data to the sparse file, in response to the identifying the first block of data;

creating a second point-in-time image of the volume in the sparse file, wherein

the second point-in-time image is represented in the sparse format, and

the creating the second point-in-time image comprises;

identifying a second block of data within the volume, wherein

the second block of data is identified in response to being modified subsequent to the particular point in time, and

storing a copy of the second block of data to the sparse file, in response to the identifying the second block of data;

and

performing an administrative action on the first and second point-in-time images stored within the sparse file, wherein

the performing comprises specifying the sparse file as a target of a file-specific command,

the file-specific command is one of a plurality of file system commands, and

the performing is performed by a computing device implementing a data protection utility.

2. The method of claim 1, wherein the storing the copy of the first block of data further comprises:

advancing to a new location in the sparse file without writing to one or more intervening locations; and

writing a value of the first block of data at the new location in the sparse file.

3. The method of claim 1, further comprising:

storing a third point-in-time image of the volume in a second sparse file.

4. The method of claim 3, further comprising:

storing a full image of the volume in a third sparse file.

5. The method of claim 1, further comprising:

exporting the sparse file as a new block device.

6. The method of claim 1, further comprising:

reducing an amount of space required to store the first and second point-in-time images by compressing the sparse file.

7. The method of claim 1, further comprising:

replicating the volume by copying the sparse file to a remote location.

8. The method of claim 1, further comprising:

initiating an operation that will increase the size of the sparse file, wherein

the initiating causes a file system to allocate additional storage space to the sparse file.

9. The method of claim 1, wherein

the sparse file includes a plurality of units of data,

metadata is associated with the sparse file, and

the metadata identifies which of the units of data are included in each of the first and second point-in-time images.

10. The method of claim 1, further comprising:

performing a file system operation on the sparse file.

11. The method of claim 1, further comprising:

using a file-sharing protocol to share access to the first and second point-in-time images.

12. The method of claim 1, further comprising:

performing at least one of;

cataloging, versioning, and archiving of the first and second point-in-time images.

13. A computer readable storage medium comprising program instructions executable to implement a data protection utility, wherein the data protection utility is configured to:

create a first point-in-time image of a volume in a sparse file, wherein

the first point-in-time image is represented in a sparse format, and

creation of the first point-in-time image comprises;

identifying a first block of data within the volume, wherein the first block of data is identified in response to being modified subsequent to a particular point in time, and

storing a copy of the first block of data to the sparse file, in response to the identifying the first block of data;

create a second point-in-time image of the volume in the sparse file, wherein

the second point-in-time image is represented in the sparse format, and

creation of the second point-in-time image comprises;

identifying a second block of data within the volume, wherein

the second block of data is identified in response to being modified subsequent to the particular point in time, and

storing a copy of the second block of data to the sparse file, in response to the identifying the second block of data and

perform an administrative action on the first and second point-in-time images stored within the sparse file, wherein

performance of the administrative action comprises specifying the sparse file as a target of a file-specific command, and

the file-specific command is one of a plurality of file system commands.

14. The computer readable storage medium of claim 13, wherein the program instructions are executable to store the first block of data to the sparse file by:

advancing to a new location in the sparse file without writing to one or more intervening locations; and

writing a value of the first block of data at the new location in the sparse file.

15. The computer readable storage medium of claim 14, wherein the program instructions are further executable to:

export the sparse file as a new block device.

16. The computer readable storage medium of claim 14, wherein the program instructions are further executable to:

replicate the volume by copying the sparse file to a remote location.

17. The computer readable storage medium of claim 13, wherein

the sparse file includes a plurality of units of data,

metadata is associated with the sparse file, and

the metadata identifies which of the units of data are included in each of the first and second of point-in-time images.

18. A system comprising:

one or more computer readable storage media, wherein the one or more computer readable storage media implement a volume;

means for creating a first point-in-time image of the volume in a sparse file, wherein the first point-in-time image is represented in a sparse format;

means for identifying a first block of data within the volume, wherein the first block of data is identified in response to being modified subsequent to a particular point in time;

means for storing a copy of the first block of data to the sparse file, in response to identification of the first block of data;

means for creating a second point-in-time image of the volume in a sparse file, wherein the second point-in-time image is represented in the sparse format;

means for identifying a second block of data within the volume, wherein the second block of data is identified in response to being modified subsequent to the particular point in time;

means for storing a copy of the second block of data to the sparse file, in response to identification of the second block of data; and

means for performing an administrative action on the first and second point-in-time images stored within the sparse file, wherein

performing the administrative action comprises specifying the sparse file as a target of a file-specific command, and

the file-specific command is one of a plurality of file system commands.

19. The system of claim 18, wherein the storing the copy of the first block of data to the sparse file comprises:

advancing to a new location in the sparse file without writing to one or more intervening locations; and

writing a value of the first block of data at the new location in the sparse file.

20. The system of claim 18, wherein

the sparse file includes a plurality of units of data,

metadata is associated with the sparse file, and

the metadata identifies which of the units of data are included in each of the first and second point-in-time images.

21. A system comprising:

a processor; and

a memory coupled to the processor, wherein the memory stores program instructions executable by the processor to;

create a first point-in-time image of a volume in a sparse file, wherein

the first point-in-time image is represented in a sparse format, and creation of the first point-in-time image comprises;

identifying a first block of data within the volume, wherein the first block of data is identified in response to being modified subsequent to a particular point in time, and

storing a copy of the first block of data to the sparse file, in response to the identifying the first block of data;

create a second point-in-time image, of the volume in the sparse file wherein

the second point-in-time image is represented in the sparse format, and

creation of the second point-in-time image comprises;

identifying a second block of data within the volume, wherein

 

the second block of data is identified in response to being modified subsequent to the particular point in time, and

storing a copy of the second block of data to the sparse file, in response to the identifying the second block of data; and

performing perform an administrative action on the first and second point-in-time images stored within the sparse file, wherein

performance of the administrative action comprises specifying the sparse file as a target of a file-specific command, and

the file-specific command is one of a plurality of file system commands.

22. The system of claim 21, wherein the program instructions are executable by the processor to store the first block of data to the sparse file by:

advancing to a new location in the sparse file without writing to one or more intervening locations; and

writing a value of the first block of data at the new location in the sparse file.

23. The system of claim 21, wherein

the sparse file includes a plurality of units of data,

metadata is associated with the sparse file, and

the metadata identifies which of the units of data are included in each of the first and second point-in-time images.