Method and apparatus of continuous data protection for NAS

• US 20080027998A1
• Filed: 07/27/2006
• Published: 01/31/2008
• Est. Priority Date: 07/27/2006
• Status: Abandoned Application

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Hara, Junichi
• Application Number:
  US11/495,276
• Publication Number:
  US 20080027998A1
• Time in Patent Office: Days
• US Class Current: 707/200
• CPC Class Codes: G06F 16/128 Details of file system snapshots on the file-level, e.g. snapshot creation, administration, deletion use of snapshots for error detection or correction G06F11/14, G06F11/16
• CPC Class Codes: G06F 16/183 Provision of network file services by network file servers, e.g. by using NFS, CIFS network file access protocols H04L67/1097

Abstract

A system includes a NAS System and one or more NAS Clients. The NAS system manages volumes containing file system data, volumes containing snapshot (copy) of the file system data, and volumes containing journal (log) of requests sent from NAS Clients. The system takes a snapshot of the volume containing file system data periodically, and records requests to the file system data after the snapshot is taken. When the system needs to restore an image of file system data at a certain point, it restores the snapshot, and then it replays the recorded requests in order. The system protects a file system using CDP function on a storage system by implementing a function in the NAS system, which determines a time point at which each storage system operation is completed, and a function in the storage system for keeping the information in the journal.

Claims

1. A computerized data storage system comprising:

a. a network-attached storage system comprising a file system volume, a snapshot volume and a journal volume; and

b. a network-attached storage client coupled to the network-attached storage system and operable to issue requests to the network-attached storage system, wherein the network-attached storage system is operable to;

i. store data in the file system volume;

ii. store snapshot image of the data in the file system volume in the snapshot volume;

iii. store information on the requests in the journal volume; and

iv. in response to a restore command issued by the network-attached storage client, to apply records from the journal volume to the content of the snapshot volume.

2. The computerized data storage system of claim 1, wherein the requests are NFS requests.

3. The computerized data storage system of claim 1, wherein the network-attached storage system is operable to store information in the journal volume only on requests, which involve modification of the data.

4. The computerized data storage system of claim 1, wherein the journal volume comprises journal records comprising journal header and journal data.

5. The computerized data storage system of claim 1, further comprising a file handle store operable to store a mapping between file handle and path of data stored by the file system volume.

6. The computerized data storage system of claim 5, wherein the network-attached storage system is further operable to obtain the file handle from the requests, verify whether the obtained file handles are stored in the file handle store and, if not, to obtain the path and to store the file handle and the path to the file handle store.

7. The computerized data storage system of claim 5, wherein upon restore of the data in the file system volume to a new volume, the network-attached storage system is further operable to use the contents of the file handle store to generate file handle information for the new volume.

8. The computerized data storage system of claim 7, wherein upon restore of the data in the file system volume to a new volume, the network-attached storage system is further operable to:

a. Get file handle from the request information stored in the journal volume;

b. Get corresponding path for the file handle from the file handle store;

c. Lookup the path within a restored file system; and

d. Replay a request for the file handle.

9. The computerized data storage system of claim 1, wherein the network-attached storage system is further operable to assign a sequence number to each request information stored in the journal volume.

10. The computerized data storage system of claim 1, wherein the network-attached storage system is further operable to determine the available journal capacity and, if the determined journal capacity is below a predetermined threshold, to delete at least some journal records.

11. The computerized data storage system of claim 1, wherein the network-attached storage system is further operable to determine the available snapshot volume capacity and, if the determined snapshot volume capacity is below a predetermined threshold, to delete at least some snapshots.

12. A method comprising:

a. Creating a journal group, the journal group comprising a file system associated with a network-attached storage and a journal volume;

b. Journaling NFS requests directed to the file system, wherein journaling comprises assigning a first sequence number to each journaled NFS request; and

c. Taking a snapshot of data in the file system, wherein taking a snapshot comprises assigning a second sequence number to the snapshot.

13. The method of claim 12, further comprising:

a. Receiving a restore command; and

b. In response to the received restore command, applying at least a portion of the journaled NFS requests to the snapshot to restore data image.

14. The method of claim 12, wherein the restore command specifies the restore data time.

15. The method of claim 12, wherein the journaled NFS requests involve modification of the data.

16. The method of claim 12, wherein the NFS requests are journaled in a journal volume storing journal records comprising journal header and journal data.

17. The method of claim 16, further comprising determining available journal volume capacity and, if the determined journal volume capacity is below a predetermined threshold, deleting at least some journal records.

18. The method of claim 13, further comprising creating a mapping between a file handle and path of data stored by the file system.

19. The method of claim 18, further comprising:

i. obtaining the file handle from the NFS requests,

ii. verifying whether the obtained file handles are stored in the file handle store and, if not, obtaining the path and storing the file handle and the path.

20. The method of claim 18, wherein applying comprises using the mapping between a file handle and path to generate file handle information for a new volume to which the file system is restored.

21. The method of claim 18, further comprising:

a. obtaining file handle from the journaled NFS requests;

b. obtaining corresponding path for the file handle from the mapping;

c. performing lookup of the path within a restored file system; and

d. replaying a request for the file handle.

22. The method of claim 18, wherein the network-attached storage system is further operable to determine the available journal capacity and, if the determined journal capacity is below a predetermined threshold, to delete at least some journal records.

23. The method of claim 18, further comprising:

a. storing the snapshot in a snapshot volume;

b. determine the available snapshot volume capacity; and

c. if the determined snapshot volume capacity is below a predetermined threshold, deleting at least some stored snapshots.

24. A computer programming product embodied in a computer-readable medium, comprising:

a. Code for creating a journal group, the journal group comprising a file system associated with a network-attached storage and a journal volume;

b. Code for journaling NFS requests directed to the file system, wherein journaling comprises assigning a first sequence number to each journaled NFS request; and

c. Code for taking a snapshot of data in the file system, wherein taking a snapshot comprises assigning a second sequence number to the snapshot.

25. The computer programming product of claim 24, further comprising:

a. Code for receiving a restore command; and

b. Code for applying at least a portion of the journaled NFS requests to the snapshot to restore data image in response to the received restore command.

26. The computer programming product of claim 24, wherein the restore command specifies the restore data time.

27. The computer programming product of claim 24, wherein the journaled NFS requests involve modification of the data.

28. The computer programming product of claim 24, wherein the NFS requests are journaled in a journal volume storing journal records comprising journal header and journal data.

29. The computer programming product of claim 24, further comprising code for determining available journal volume capacity and, if the determined journal volume capacity is below a predetermined threshold, deleting at least some journal records.

30. The computer programming product of claim 24, further comprising code for creating a mapping between a file handle and path of data stored by the file system.

31. The computer programming product of claim 24, further comprising:

i. Code for obtaining the file handle from the NFS requests,

ii. Code for verifying whether the obtained file handles are stored in the file handle store and, if not, obtaining the path and storing the file handle and the path.

32. The computer programming product of claim 24, wherein applying comprises using the mapping between a file handle and path to generate file handle information for a new volume to which the file system is restored.

33. The computer programming product of claim 24, further comprising:

a. Code for obtaining file handle from the journaled NFS requests;

b. Code for obtaining corresponding path for the file handle from the mapping;

c. Code for performing lookup of the path within a restored file system; and

d. Code for replaying a request for the file handle.

34. The computer programming product of claim 24, further comprising:

a. Code for storing the snapshot in a snapshot volume;

b. Code for determine the available snapshot volume capacity; and

, if the determined snapshot volume capacity is below a predetermined threshold, deleting at least some stored snapshots.