Method and system for restoring data

• US 20050193239A1
• Filed: 02/13/2004
• Published: 09/01/2005
• Est. Priority Date: 02/13/2004
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Shackelford, David Michael
• Granted Patent: US 7,475,211 B2
• Time in Patent Office: Days
• US Class Current: 714/6.32
• CPC Class Codes: G06F 11/1469 Backup restoration techniques

Abstract

One aspect of the invention is a method for restoring data, which for example, includes receiving a request for at least a portion of the data. This example also includes creating a directory entry for the data in a virtual file system, and allocating storage space for the data. This example further includes initializing a block virtualization indicator to a value indicating that the data is not available. This example additionally includes writing a subset of the data to the storage space, and changing the block virtualization indicator to a value indicating that the data is available.

Claims

1. A signal bearing medium tangibly embodying a program of machine-readable instructions executable by a digital processing apparatus to perform operations for restoring data, the operations comprising:

receiving a request for at least a portion of the data;

creating a directory entry for the data in a virtual file system;

allocating storage space for the data;

initializing a block virtualization indicator to a value indicating that the data is not available;

writing a subset of the data to the storage space; and

changing the block virtualization indicator to a value indicating that the data is available.

2. The signal bearing medium of claim 1, wherein the operations further comprise writing an additional subset of the data to the storage space.

3. The signal bearing medium of claim 1, wherein the operations further comprise identifying portions of the data that have not been written to the storage space.

4. The signal bearing medium of claim 1, wherein the operations further comprise:

receiving a request for a part of the data that at least partially is not written to the storage space;

retrieving and writing to the storage space the requested part of the data that is not written to the storage space; and

responding to the request for the part of the data.

5. The signal bearing medium of claim 4, wherein the requested part of the data that is not written to the storage space is retrieved on a priority basis.

6. The signal bearing medium of claim 4, wherein the operations further comprise indicating a busy condition.

7. The signal bearing medium of claim 4, wherein the operations further comprise retrieving an additional subset of the data, starting at a location sequentially after the retrieved data.

8. The signal bearing medium of claim 4, wherein the operations further comprise retrieving an additional subset of the data, starting at a location wherein data is expected to be requested next.

9. The signal bearing medium of claim 4, wherein the operations further comprise retrieving an additional subset of the data, starting at a randomly selected location.

10. The signal bearing medium of claim 1, wherein the operations further comprise:

identifying if an application performs a write that does not require a read/modify/write on a block of the data that has not yet been restored; and

if so,

marking the block of the data as discarded.

11. The signal bearing medium of claim 1, wherein the operations further comprise backing up the data.

12. The signal bearing medium of claim 11, wherein the operation of backing up the data comprises storing information identifying the storage locations of each of a plurality of blocks of the data.

13. The signal bearing medium of claim 11, wherein the operation of backing up the data further comprises storing metadata including access characteristics of blocks of the data, with the data.

14. The signal bearing medium of claim 11, wherein the operations further comprise associating with the data, metadata indicating access characteristics of blocks of the data.

15. The signal bearing medium of claim 1, wherein the operation of creating a directory entry further comprises creating a pointer for the data in the virtual file system.

16. The signal bearing medium of claim 1, wherein the data is restored from tape.

17. A signal bearing medium tangibly embodying a program of machine-readable instructions executable by a digital processing apparatus to perform operations for restoring data, the operations comprising:

restoring the data into a storage virtualization engine;

using special entries in a virtualization mapping to indicate that the data is temporarily unavailable;

retrieving a subset of the data and writing the subset of the data to a storage space;

releasing the data for application access; and

delaying completion of I/O requests for accesses to portions of the data that are identified as being unavailable in an unavailable mapping.

18. A signal bearing medium tangibly embodying a program of machine-readable instructions executable by a digital processing apparatus to perform operations for restoring data, the operations comprising:

storing access metadata with the data;

creating a directory entry for the data in a virtual file system and allocating space for the data;

initializing a block virtualization to be equal to a “

not present being restored”

value;

begin restoring the data in blocks in an order in which references to the blocks are expected;

allowing an application to begin using the restored data, after a subset of the data has been restored using the order in which references to the blocks are expected; and

delaying a read and placing a priority restore action in a restore queue, if the application attempts to read from a block of the data that has not been restored.

19. A computing system, comprising:

a memory; and

a processing device coupled to the memory, wherein the processing device is programmed to perform operations for restoring data, the operations comprising;

receiving a request for at least a portion of the data;

creating a directory entry for the data in a virtual file system;

allocating storage space for the data;

initializing a block virtualization indicator to a value indicating that the data is not available;

writing a subset of the data to the storage space; and

changing the block virtualization indicator to a value indicating that the data is available.

20. The computing system of claim 19, wherein the memory and the processing device are part of a host, and further comprising:

a file virtualization meta data server coupled to the host; and

a storage virtualization engine SAN volume controller coupled to the host.

21. The computing system of claim 20, further comprising a disk device and a backup device coupled to the storage virtualization engine SAN volume controller.

22. A computing system, comprising:

means for receiving a request for at least a portion of data;

means for creating a directory entry for the data in a virtual file system;

means for allocating storage space for the data;

means for initializing a block virtualization indicator to a value indicating that the data is not available;

means for writing a subset of the data to the storage space; and

means for changing the block virtualization indicator to a value indicating that the data is available.

23. A method for restoring data, comprising the following operations:

receiving a request for at least a portion of the data;

creating a directory entry for the data in a virtual file system;

allocating storage space for the data;

initializing a block virtualization indicator to a value indicating that the data is not available;

writing a subset of the data to the storage space; and

changing the block virtualization indicator to a value indicating that the data is available.

24. The method of claim 23, wherein the operations further comprise identifying portions of the data that have not been written to the storage space.

25. The method of claim 23, wherein the operations further comprise:

receiving a request for a part of the data that at least partially is not written to the storage space;

retrieving and writing to the storage space the requested part of the data that is not written to the storage space; and

responding to the request for the part of the data.

26. The method of claim 23, wherein the operations further comprise associating with the data, metadata indicating access characteristics of blocks of the data.