High speed backup
High speed backup of a target volume to a VHD format is disclosed. In various embodiments, a hint data indicating a last known file system extent associated with a previously-processed data zone is received. The hint data is used to determine a starting file system extent at which to begin processing file system extent data of the target volume to find file system extents associated with a VHD data zone that is currently being processed.
1. A method of backing up data of a target volume to a virtual hard disk (VHD) format, comprising:
receiving a hint data indicating a last known file system extent associated with a previously-processed data zone;
using the hint data to determine a starting file system extent at which to begin processing file system extent data of the target volume to find file system extents associated with a VHD data zone that is currently being processed; and
backing up the data of the target volume at least in part by using the hint data to skip over one or more file system extents found previously to be associated with one or more previously-processed VHD data zones.
2. The method of claim 1 , further comprising passing to a calling module, at the conclusion of processing file system extent data for the VHD data zone that is currently being processed, a current hint data indicating a last known file system extent index determined to be associated with the VHD data zone the processing of which was just concluded.
3. The method of claim 1 , wherein the hint data comprises a cookie.
4. The method of claim 1 , wherein the hint data comprises a file system extent index.
5. The method of claim 1 , wherein the hint is received from a calling module.
6. The method of claim 1 , wherein successive VHD data zones are processed in an ascending order.
7. The method of claim 1 , further comprising using the file system extents determined to be associated with the VHD data zone that is currently being processed to generate a sector bitmap for the VHD data zone that is currently being processed.
8. The method of claim 7 , further comprising writing the sector bitmap for the VHD data zone that is currently being processed to an output stream.
9. The method of claim 7 , further comprising writing the sector bitmap for the VHD data zone that is currently being processed to a backup media.
10. A system to back up data of a target volume to a virtual hard disk (VHD) format, comprising:
a processor configured to:
receive a hint data indicating a last known file system extent associated with a previously-processed data zone;
use the hint data to determine a starting file system extent at which to begin processing file system extent data of the target volume to find file system extents associated with a VHD data zone that is currently being processed; and
back up the data of the target volume at least in part by using the hint data to skip over one or more file system extents found previously to be associated with one or more previously-processed VHD data zones; and
a memory coupled to the processor and configured to store the hint data.
11. The system of claim 10 , wherein the processor is further configured to pass to a calling module, at the conclusion of processing file system extent data for the VHD data zone that is currently being processed, a current hint data indicating a last known file system extent index determined to be associated with the VHD data zone the processing of which was just concluded.
12. The system of claim 10 , wherein the hint data comprises a cookie.
13. The system of claim 10 , wherein the hint data comprises a file system extent index.
14. The system of claim 10 , wherein successive VHD data zones are processed in an ascending order.
15. The system of claim 10 , wherein the processor is further configured to use the file system extents determined to be associated with the VHD data zone that is currently being processed to generate a sector bitmap for the VHD data zone that is currently being processed.
16. The system of claim 15 , wherein the processor is further configured to write the sector bitmap for the VHD data zone that is currently being processed to an output stream.
17. The system of claim 15 , wherein the processor is further configured to write the sector bitmap for the VHD data zone that is currently being processed to a backup media.
18. A computer program product to back up data of a target volume to a virtual hard disk (VHD) format, the computer program product being embodied in a tangible, non-transitory computer readable storage medium and comprising computer instructions for:
receiving a hint data indicating a last known file system extent associated with a previously-processed data zone;
using the hint data to determine a starting file system extent at which to begin processing file system extent data of the target volume to find file system extents associated with a VHD data zone that is currently being processed; and
backing up the data of the target volume at least in part by using the hint data to skip over one or more file system extents found previously to be associated with one or more previously-processed VHD data zones.
19. The computer program product of claim 18 , wherein the hint data comprises a cookie.
20. The computer program product of claim 18 , wherein the hint data comprises a file system extent index.