Methods and devices for restoring a portion of a data store

• US 20050076264A1
• Filed: 08/24/2004
• Published: 04/07/2005
• Est. Priority Date: 09/23/2003
• Status: Active Grant

• Current Assignee: Veritas Technologies, LLC (Whitehouse Group Ltd.)
• Original Assignee: Symantec Operating Corporation (Gen Digital Inc.)
• Inventors: Rowan, Michael, Rodgers, Kevin
• Granted Patent: US 7,577,807 B2
• Time in Patent Office: Days
• US Class Current: 714/6
• CPC Class Codes: G06F 11/1461 Backup scheduling policy
• CPC Class Codes: G06F 11/1469 Backup restoration techniques
• CPC Class Codes: G06F 11/1471 involving logging of persistent data for recovery

Abstract

A storage management device receives a request to restore a portion of a data store to its content at a specified past time, which is selected from a substantially continuous time interval. In response to the received request, the storage management device stores in the portion of the data store content that was stored in the portion of the data store at the specified past time and that was overwritten since the specified past time.

Claims

1. A method for restoring a portion of a data store, the method comprising:

receiving a request to restore a portion of a data store to its content at a specified past time, the specified past time selected from a substantially continuous time interval;

storing in the portion of the data store content that was stored in the portion of the data store at the specified past time and that was overwritten since the specified past time.

2. The method of claim 1, wherein the storing step comprises:

identifying units of storage within the portion of the data store that had content stored in those units of storage at the specified past time and that had that content overwritten since the specified past time; and

writing to the identified units of storage the content that was stored in those identified units of storage at the specified past time.

3. The method of claim 2, wherein the identifying step comprises determining whether units of storage located within the portion of the data store were overwritten in the interval between the specified past time and a present time.

4. The method of claim 3, wherein the identifying step further comprises, for each determined unit of storage that was overwritten in the interval between the specified past time and a present time, locating a stored copy of the content that was overwritten.

5. The method of claim 4, wherein the stored copy is located by locating the content associated with the first write operation following the specified past time directed to such unit of storage.

6. The method of claim 5, wherein the stored copy was made during the execution of a copy-on-write operation.

7. The method of claim 5, wherein the stored copy was recorded in a time store.

8. The method of claim 5, wherein the stored copy was stored in a collection of changes to the data store.

9. The method of claim 8, wherein the collection is a database.

10. The method of claim 2, wherein the writing step comprises performing for at least one of the identified units of storage a copy-on-write operation.

11. The method of claim 2, wherein the writing step comprises copying current content currently stored in each identified unit of storage before such current content is overwritten.

12. The method of claim 11, wherein copying the current content comprises storing the current content at a location different than the portion of the data store.

13. The method of claim 1, wherein the portion of the data store comprises contiguous units of storage.

14. The method of claim 1, wherein the portion of the data store comprises non-contiguous units of storage.

15. The method of claim 1, wherein the portion of the data store comprises the portion of a data store storing data for an application.

16. The method of claim 1, wherein the request is included in a request to restore all or portions of each of a plurality of data stores.

17. The method of claim 1 further comprising servicing an I/O request directed to the portion of the data store while storing in the portion of the data store the content that was stored in the portion of the data store at the specified past time and that was overwritten since the specified past time.

18. A method for restoring a portion of a data store, the method comprising:

receiving a request to restore a portion of a data store to its content at a specified past time, the specified past time selected from a substantially continuous time interval; and

in response to the request, for each unit of storage in the portion;

determining whether such unit of storage was overwritten in the interval between the specified past time and a present time; and

in response to the determining step, for each unit of storage determined to have been overwritten in the interval between the specified past time and a present time;

locating a stored copy of the overwritten content;

copying the content currently in the determined unit of storage to a respective saved unit of storage;

storing in the determined unit of storage the located previously overwritten content; and

recording the occurrence of the storing step and the associated location of the respective saved unit of storage.

19. A device for restoring a portion of a data store, the device comprising:

a receiver configured to receive a request to restore a portion of a data store to its content at a specified past time, the specified past time selected from a substantially continuous time interval; and

a storing module configured to store in the portion of the data store content that was stored in the portion of the data store at the specified past time and that was overwritten since the specified past time.