Granted Patent B1

US 8,775,377 · App. 13/557,558 · Granted Jul 8, 2014

Inventors: Shuangmin Zhang (Beijing, CN); Xianbo Zhang (Plymouth, MN); Weibao Wu (Vadnais Heights, MN); Jim R. Lamb (Maplewood, MN); Yun Yang (Beijing, CN); Satyajit Ashok GorheParlikar (Shoreview, MN)

Assignee: Symantec Corporation

G06F17/00

Abstract

Claims (74)

1. A non-transitory computer readable storage medium configured to store program instructions that, when executed on a processor, are configured to cause the processor to perform a method comprising:

receiving data at a backup server, wherein the data comprises a header;

determining whether the header comprises a metadata header; and

in response to a determination that the header comprises the metadata header,

extracting metadata from the metadata header, wherein

the metadata identifies unchanged file data in a previous backup image,

extracting a copy of the unchanged file data from the previous backup image, using the metadata, and

writing the copy of the unchanged file data to a present backup image.

2. The non-transitory computer readable storage medium of claim 1 , wherein the method further comprises:

in response to a determination that the header does not comprise the metadata header,

writing changed file data associated with the header to the present backup image, wherein

the data comprises the changed file data.

3. The non-transitory computer readable storage medium of claim 1 , wherein

the extracting the copy of the unchanged file data further comprises

identifying the previous backup image using a backup image identifier extracted from the metadata header.

4. The non-transitory computer readable storage medium of claim 1 , wherein the method further comprises:

verifying integrity of the copy of the unchanged file data using a first fingerprint extracted from the metadata header.

5. The non-transitory computer readable storage medium of claim 4 , wherein

the verifying integrity comprises

generating a second fingerprint of the copy of the unchanged file data, and

determining whether the second fingerprint matches the first fingerprint.

6. The non-transitory computer readable storage medium of claim 1 , wherein

the metadata comprises a location of the unchanged file data in the previous backup image.

7. The non-transitory computer readable storage medium of claim 1 , wherein

the present backup image is a full backup image.

8. A method comprising:

receiving data at a backup server, wherein the data comprises a header;

determining whether the header comprises a metadata header; and

in response to a determination that the header comprises the metadata header,

extracting metadata from the metadata header, wherein

the metadata identifies unchanged file data in a previous backup image,

extracting a copy of the unchanged file data from the previous backup image, using the metadata, and

writing the copy of the unchanged file data to a present backup image.

9. The method of claim 8 , further comprising:

in response to a determination that the header does not comprise the metadata header,

writing changed file data associated with the header to the present backup image, wherein

the data comprises the changed file data.

10. The method of claim 8 , wherein

the extracting the copy of the unchanged file data further comprises

identifying the previous backup image using a backup image identifier extracted from the metadata header.

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

verifying integrity of the copy of the unchanged file data using a first fingerprint extracted from the metadata header.

12. The method of claim 11 , wherein

the verifying integrity comprises

generating a second fingerprint of the copy of the unchanged file data, and

determining whether the second fingerprint matches the first fingerprint.

13. The method of claim 8 , wherein

the metadata comprises a location of the unchanged file data in the previous backup image.

14. The method of claim 8 , wherein

the present backup image is a full backup image.

15. A computing device comprising:

a processor; and

a memory coupled to the processor and configured to store instructions executable by the processor, the instructions configured to implement

a backup server module configured to

receive data, wherein the data comprises a header,

an analysis module configured to

determine whether the header comprises a metadata header,

extract metadata from the metadata header, in response to a determination that the header comprises the metadata header, wherein

the metadata identifies unchanged file data in a previous backup image, and

a transmit module configured to

extract a copy of the unchanged file data from the previous backup image, using the metadata, and

write the copy of the unchanged file data to a present backup image.

16. The computing device of claim 15 , wherein the transmit module is further configured to:

write changed file data associated with the header to the present backup image, in response to a determination that the header does not comprise the metadata header, wherein the data comprises the changed file data.

17. The computing device of claim 15 , wherein the transmit module is further configured to:

identify the previous backup image using a backup image identifier extracted from the metadata header.

18. The computing device of claim 15 , wherein the instructions are further configured to implement:

a fingerprint generation module configured to

verify integrity of the copy of the unchanged file data using a first fingerprint extracted from the metadata header.

19. The computing device of claim 18 , wherein the fingerprint generation module is further configured to:

generate a second fingerprint of the copy of the unchanged file data, and

determine whether the second fingerprint matches the first fingerprint.

20. The computing device of claim 15 , wherein

the metadata comprises a location of the unchanged file data in the previous backup image.

Assignments (14)