VIRTUAL MACHINE DATA REPLICATION

• US 20100262586A1
• Filed: 04/12/2010
• Published: 10/14/2010
• Est. Priority Date: 04/10/2009
• Status: Active Grant

• Current Assignee: Datto LLC
• Original Assignee: PHD Virtual Technologies
• Inventors: McKelvey, Ronald T., Mittell, Alexander D., ROSIKIEWICZ, JAMES
• Granted Patent: US 8,135,748 B2
• Time in Patent Office: Days
• US Class Current: 707/679
• CPC Class Codes: G06F 11/1438 Restarting or rejuvenating
• CPC Class Codes: G06F 11/1469 Backup restoration techniques
• CPC Class Codes: G06F 11/1484 involving virtual machines
• CPC Class Codes: G06F 16/10 File systems; File servers

Abstract

Disclosed is a method and system for selectively restoring file-level data from a disk image backup. In embodiments, a virtual machine backup may be performed by dividing a virtual machine virtual disk file into a plurality of discrete fixed-sized data blocks sharing a common index file that is stored on a backup medium, such as a hard drive, to form a backup set. Upon restoration of data from the backup set, individual blocks of the data set are compared to corresponding blocks of the target virtual machine file. Redundant data and unchanged blocks are skipped, and only those block which have changed are restored to the target file. In this manner network bandwidth and processor resources are conserved, and replication times decreased.

Claims

1. A method for restoring to a first storage device a virtual machine file data from a second storage device containing a backup set of the virtual machine data file, the backup set including at least one backup datablock and an index file, comprising the steps of:

identifying a backup data block of the backup set corresponding to a target data block of the virtual machine file;

evaluating whether a corresponding target data block has changed since a previous restoration; and

writing the backup data block to the target data block in response to an evaluation that the corresponding target data block has changed since a previous restoration.

2. The method in accordance with claim 1, wherein the evaluating step is performed at least in part by comparing a hash value of the backup data block to a hash value of the target data block.

3. The method in accordance with claim 2, wherein the hash value is computed in accordance with an MD5 algorithm

4. The method in accordance with claim 1, further comprising determining whether the first storage device virtual machine data file was previously restored.

5. The method in accordance with claim 1, wherein a virtual machine data file includes a previous restore flag.

6. The method in accordance with claim 5, wherein a previous restore flag indicates the virtual machine data file was restored at least partially from a backup set.

7. The method in accordance with claim 1, wherein the previous restore flag includes a timestamp.

8. The method in accordance with claim 1, further comprising the steps of:

computing a hash value corresponding to a stored datablock;

determining whether the computed hash value is equal to a stored hash value corresponding to the stored datablock;

causing the entirety of the backup set to be written to the first storage device responsive to a determination that the computed hash value does not equal the stored hash value.

17. Machine-readable media comprising a set of instructions configured to perform the method in accordance with claims 1 though 8.

9. A system for performing data restoration, comprising:

a processor;

a storage device operably coupled to the processor; and

a data backup module including a set of instructions executable on the processor for performing a method of data backup comprising the steps of;

identifying a backup data block of the backup set corresponding to a target data block of the virtual machine file;

evaluating whether a corresponding target data block has changed since a previous restoration; and

writing the backup data block to the target data block in response to an evaluation that the corresponding target data block has changed since a previous restoration.

10. The system in accordance with claim 9, wherein the evaluation step of the method is performed at least in part by comparing a hash value of the backup data block to a hash value of the target data block.

11. The system in accordance with claim 9, wherein the hash value is computed in accordance with an MD5 algorithm

12. The system in accordance with claim 9, further comprising determining whether the first storage device virtual machine data file was previously restored.

13. The system in accordance with claim 9, wherein a virtual machine data file includes a previous restore flag.

14. The system in accordance with claim 13, wherein a previous restore flag indicates the virtual machine data file was restored at least partially from a backup set.

15. The system in accordance with claim 13, wherein the previous restore flag includes a timestamp.

16. The system in accordance with claim 9, wherein the method further comprises the steps of:

computing a hash value corresponding to a stored datablock;

determining whether the computed hash value is equal to a stored hash value corresponding to the stored datablock;

causing the entirety of the backup set to be written to the first storage device responsive to a determination that the computed hash value does not equal the stored hash value.