Method, apparatus and computer program product for data backup
Embodiments of the present disclosure provide a method, apparatus and computer program product for data backup. A method includes obtaining first information about data change in a virtual disk, where the first information indicates that data in at least one block of a plurality of blocks is changed. The method also includes determining, based on the first information, second information about a location of the at least one block in the virtual disk. The method further includes obtaining a first size of the virtual disk backed up to a backup server prior to the data change and a second size of the virtual disk subsequent to the data change. In addition, the method includes generating, based on the second information, the first size and the second size, incremental backup data for backing up the virtual disk having the second size to the backup server.
1. A method of data backup, comprising:
obtaining first information that indicates changed data in a first block of a plurality of blocks of a local virtual disk, wherein the local virtual disk is an expandable virtual disk;
determining, based on the first information, a block location of the first block in the local virtual disk;
obtaining a first size of a backup virtual disk stored on a backup server;
obtaining a second size of the local virtual disk subsequent to the data change, wherein the first size is smaller than the second size; and
generating incremental backup data for the local virtual disk, wherein generating the incremental backup data comprises:
determining, based on the first size, a first end location of the local virtual disk prior to the data change;
determining, based on the second size, a second end location of the local virtual disk subsequent to the data change;
generating, for a second block of the plurality of blocks, an indication to fill a corresponding second block of the backup virtual drive with a predetermined value, wherein the second block is located after the first end location; and
generating the incremental backup data based on the block location, the first end location, and the second end location, wherein the incremental backup data comprises the indication and the changed data.
2. The method of claim 1 , further comprising:
sending the incremental backup data to the backup server.
3. The method of claim 1 , wherein the local virtual disk is a virtual disk in a Hyper-V system, and obtaining the first information comprises:
obtaining, from the Hyper-V system, Resilient Change Tracking (RCT) data relating to the local virtual disk.
4. The method of claim 1 , wherein determining the block location comprises:
determining one selected from the group consisting of a size of the first block, a start location of the first block, and an end location of the first block.
5. The method of claim 1 , wherein generating the incremental backup data comprises:
generating, for a third block of the plurality of blocks, a reference to backup data of a corresponding third block of the backup virtual disk, wherein the third block is located before the first end location, wherein the incremental backup data further comprises the reference.
6. An apparatus for data backup, comprising:
a processing unit; and
memory coupled to the processing unit and storing instructions which, when executed by the processing unit, cause the apparatus to perform a method, the method comprising:
obtaining first information that indicates changed data in a first block of a plurality of blocks of a local virtual disk, wherein the local virtual disk is an expandable virtual disk;
determining, based on the first information, a block location of the first block in the local virtual disk;
obtaining a first size of a backup virtual disk stored on a backup server;
obtaining a second size of the local virtual disk subsequent to the data change, wherein the first size is smaller than the second size; and
generating incremental backup data for the local virtual disk, wherein generating the incremental backup data comprises:
determining, based on the first size, a first end location of the local virtual disk prior to the data change;
determining, based on the second size, a second end location of the local virtual disk subsequent to the data change;
generating, for a second block of the plurality of blocks, an indication to fill a corresponding second block of the backup virtual drive with a predetermined value, wherein the second block is located after the first end location; and
generating the incremental backup data based on the block location, the first end location, and the second end location, wherein the incremental backup data comprises the indication and the changed data.
7. The apparatus of claim 6 , wherein the method further comprises:
sending the incremental backup data to the backup server.
8. The apparatus of claim 6 , wherein the local virtual disk is a virtual disk in a Hyper-V system, and obtaining the first information comprises:
obtaining, from the Hyper-V system, Resilient Change Tracking (RCT) data relating to the local virtual disk.
9. The apparatus of claim 6 , wherein determining the block location comprises:
determining one selected from the group consisting of a size of the first block, a start location of the first block, and an end location of the first block.
10. The apparatus of claim 6 , wherein generating the incremental backup data comprises:
generating, for a third block of the plurality of blocks, a reference to backup data of a corresponding third block of the backup virtual disk, wherein the third block is located before the first end location, wherein the incremental backup data further comprises the reference.
11. A non-transitory computer readable medium comprising instructions which, when executed by a processor, enables the processor to perform a method of data backup, the method comprising:
obtaining first information that indicates changed data in a first block of a plurality of blocks of a local virtual disk, wherein the local virtual disk is an expandable virtual disk;
determining, based on the first information, a block location of the first block in the local virtual disk;
obtaining a first size of a backup virtual disk stored on a backup server;
obtaining a second size of the local virtual disk subsequent to the data change, wherein the first size is smaller than the second size; and
generating incremental backup data for the local virtual disk, wherein generating the incremental backup data comprises:
determining, based on the first size, a first end location of the local virtual disk prior to the data change;
determining, based on the second size, a second end location of the local virtual disk subsequent to the data change;
generating, for a second block of the plurality of blocks, an indication to fill a corresponding second block of the backup virtual drive with a predetermined value, wherein the second block is located after the first end location; and
generating the incremental backup data based on the block location, the first end location, and the second end location, wherein the incremental backup data comprises the indication and the changed data.
12. The non-transitory computer readable medium of claim 11 , wherein the method further comprises:
sending the incremental backup data to the backup server.
13. The non-transitory computer readable medium of claim 11 , wherein the local virtual disk is a virtual disk in a Hyper-V system, and obtaining the first information comprises:
obtaining, from the Hyper-V system, Resilient Change Tracking (RCT) data relating to the local virtual disk.
14. The non-transitory computer readable medium of claim 11 , wherein determining the block location comprises:
determining one selected from the group consisting of a size of the first block, a start location of the first block, and an end location of the first block.
15. The non-transitory computer readable medium of claim 11 , wherein generating the incremental backup data comprises:
generating, for a third block of the plurality of blocks, a reference to backup data of a corresponding third block of the backup virtual disk, wherein the third block is located before the first end location, wherein the incremental backup data further comprises the reference.