Efficient Management of Archival Images of Virtual Machines Having Incremental Snapshots

• US 20100049929A1
• Filed: 08/25/2008
• Published: 02/25/2010
• Est. Priority Date: 08/25/2008
• Status: Active Grant

• Current Assignee: Veritas Technologies, LLC (Whitehouse Group Ltd.)
• Original Assignee: Symantec Operating Corporation (Gen Digital Inc.)
• Inventors: Nagarkar, Kuldeep S., Naftel, Timothy M.
• Granted Patent: US 8,495,316 B2
• Time in Patent Office: Days
• US Class Current: 711/162
• CPC Class Codes: G06F 11/1415 at system level
• CPC Class Codes: G06F 11/1451 by selection of backup contents
• CPC Class Codes: G06F 2201/815 Virtual
• CPC Class Codes: G06F 2201/84 Using snapshots, i.e. a logical point-in-time copy of the data
• CPC Class Codes: G06F 9/45533 Hypervisors; Virtual machine monitors

Abstract

In one embodiment, a backup application is disclosed which is configured to detect that one or more incremental virtual disk files are provided in a virtual machine image. The backup application may invoke a merge function in the virtual machine monitor, and may merge the incremental virtual disk files into the base virtual disk file. Redundant data is thus eliminated, and may reduce the amount of archive media needed to store the backed-up virtual machine image.

Claims

1. A method comprising:

determining that a virtual disk for a virtual machine is represented by a base virtual disk file and one or more incremental virtual disk files;

invoking a merge operation to merge the one or more incremental virtual disk files into the base virtual disk file responsive to the determining; and

writing a backup image comprising the merged base virtual disk file to one or more archive media.

2. The method as recited in claim 1 further comprising requesting that the virtual machine be suspended prior to the determining, wherein the suspended virtual machine is represented by a virtual machine image written to a storage.

3. The method as recited in claim 2 wherein the base virtual disk file and the one or more incremental virtual disk files are part of the image, and wherein the image further comprises other virtual machine state, and wherein the backup image further comprises the other virtual machine state.

4. The method as recited in claim 1 further comprising requesting one or more snapshots of the virtual machine, each snapshot causing a creation of one of the one or more incremental virtual disk files.

5. The method as recited in claim 4 wherein requesting the snapshot comprises requesting a volume shadow copy service portable snapshot.

6. The method as recited in claim 1 wherein the virtual machine executes on a first computer system, and wherein the determining, the invoking, and the writing are performed on the first computer system.

7. The method as recited in claim 1 wherein the virtual machine executes on a first computer system, and wherein the determining, the invoking, and the writing are performed on a second computer system coupled to the first computer system.

8. The method as recited in claim 7 further comprising preserving the unmerged base virtual disk file and the one or more incremental virtual disk files on the first computer system.

9. A computer accessible storage medium storing a plurality of instructions which, when executed:

determine that a virtual disk for a virtual machine is represented by a base virtual disk file and one or more incremental virtual disk files;

invoke a merge operation to merge the one or more incremental virtual disk files into the base virtual disk file responsive to the determining; and

write a backup image comprising the merged base virtual disk file to one or more archive media.

10. The computer accessible storage medium as recited in claim 9 wherein the plurality of instructions, when executed, request that the virtual machine be suspended prior to the determining, wherein the suspended virtual machine is represented by a virtual machine image written to a storage.

11. The computer accessible storage medium as recited in claim 10 wherein the base virtual disk file and the one or more incremental virtual disk files are part of the image, and wherein the image further comprises other virtual machine state, and wherein the backup image further comprises the other virtual machine state.

12. The computer accessible storage medium as recited in claim 9 wherein the plurality of instructions, when executed, request one or more snapshots of the virtual machine, each snapshot causing a creation of one of the one or more incremental virtual disk files.

13. The computer accessible storage medium as recited in claim 12 wherein the snapshot is a volume shadow copy service portable snapshot.

14. The computer accessible storage medium as recited in claim 9 wherein the virtual machine executes on a first computer system, and wherein the plurality of instructions also execute on the first computer system.

15. The computer accessible storage medium as recited in claim 9 wherein the virtual machine executes on a first computer system, and wherein the plurality of instructions execute on a second computer system coupled to the first computer system.

16. The computer accessible storage medium as recited in claim 15 wherein the plurality of instructions, when executed, preserve the unmerged base virtual disk file and the one or more incremental virtual disk files on the first computer system.

17. A computer system comprising:

hardware configured to execute instructions; and

a storage device coupled to the hardware, the storage device storing a virtual machine monitor executable by the hardware and a virtual machine schedulable by the virtual machine monitor to execute on the hardware, wherein the virtual machine comprises at least one virtual disk accessed by software encapsulated in the virtual machine, and wherein the virtual disk is represented by a base virtual disk file and one or more incremental virtual disk files, and wherein the storage device further stores a backup application which, when executed, invokes a merge operation to merge the one or more incremental virtual disk files into the base virtual disk file and writes a backup image comprising the merged base virtual disk file to one or more archive media.

18. The computer system as recited in claim 17 wherein the backup application executes on the computer system.

19. The computer system as recited in claim 17 wherein the backup application executes on a second computer system coupled to the computer system.

20. The computer system as recited in claim 17 wherein the backup application preserves the one or more incremental virtual disk files and the unmerged base virtual disk file.