Apparatus and method for a proxy cache

• US 20040054777A1
• Filed: 09/16/2002
• Published: 03/18/2004
• Est. Priority Date: 09/16/2002
• Status: Active Grant

• Current Assignee: NetApp, Inc.
• Original Assignee: Network Appliance Incorporated (NetApp, Inc.)
• Inventors: Grunwald, David, Ayyar, Kartik, Prakash, Ashish, Ackaouy, Emmanuel, Quirion, Brian, Amdur, Matthew
• Granted Patent: US 7,171,469 B2
• Time in Patent Office: Days
• US Class Current: 709/225
• CPC Class Codes: G06F 16/9574 of access to content, e.g. by caching
• CPC Class Codes: H04L 67/5682 Policies or rules for updating, deleting or replacing the stored data

Abstract

In one embodiment, the invention provides an apparatus for caching data in a network, with the apparatus including a proxy cache configured to receive request for an object from a client and to fetch data blocks from a server. The proxy cache may be configured to cache the data blocks in a hierarchical relationship within the object. The object may be, for example, a data file or a directory. The data blocks that are cached in the proxy cache define an active data set which is based upon a request from a client.

Claims

1. An apparatus for caching data in a network, the apparatus comprising:

a proxy cache configured to receive request for an object from a client and to fetch data blocks from a server;

the proxy cache configured to cache the data blocks in a hierarchical relationship within the object and as an active data set.

2. The apparatus of claim 1, wherein the data blocks are in a buffer tree to permit the hierarchical relationship within a file.

3. The apparatus of claim 1, wherein a data block is placed in the active data set in response to a request from a client.

4. The apparatus of claim 1, wherein the active data set comprises a portion of data stored in at least the server.

5. The apparatus of claim 1, wherein the active data set is defined by a particular time period.

6. The apparatus of claim 1, wherein the proxy cache is configured to fetch a data block from the server in response to a request from the client, if a file requested by the server is missing the data block.

7. The apparatus of claim 1, wherein the proxy cache is configured to fetch a data block from the server in response to a request from the client, if a file requested by the server is absent from the proxy cache.

8. The apparatus of claim 1, wherein the proxy cache and client communicate by use of an open standard protocol.

9. The apparatus of claim 8, wherein the protocol comprises an Internet Protocol.

10. The apparatus of claim 8, wherein the protocol comprises Network File System (NFS) protocol.

11. The apparatus of claim 8, wherein the protocol comprises Common Internet File System (CIFS) protocol.

12. The apparatus of claim 1, wherein the proxy cache computes a unique name as part of a computation to determine the presence or absence of a data block in a data file requested by a client.

13. The apparatus of claim 1, wherein a portion of the active data set can be flushed from the proxy cache based upon a replacement policy.

14. The apparatus of claim 1, wherein the object comprises a data file.

15. The apparatus of claim 1, wherein an object comprises a part of a file.

16. A method for caching data in a network, the method comprising:

receiving request for an object from a client;

if each data block in the requested object is in the cache, then sending the requested object to the client;

if a data block in the requested object is missing, then fetching the data block from a server, filling the data block in a hierarchical relationship and as part of an active data set, and sending the requested object to the client.

17. The method of claim 16, further comprising:

fetching a data block from the server in response to a request from the client, if a file requested by the server is absent.

18. The method of claim 16, wherein the data blocks are in a buffer tree to permit the hierarchical relationship within a file.

19. The method of claim 16, wherein the active data set comprises a portion of data stored in at least the server.

20. The method of claim 16, wherein the active data set is defined by a particular time period.

21. The method of claim 16, wherein the request for the object is transmitted by use of an open standard protocol.

22. The method of claim 21, wherein the protocol comprises an Internet Protocol.

23. The method of claim 21, wherein the protocol comprises Network File System (NFS) protocol.

24. The method of claim 21, wherein the protocol comprises Common Internet File System (CIFS) protocol.

25. The method of claim 16, further comprising computing a unique name as part of a computation to determine the presence or absence of a data block in a data file requested by a client.

26. The method of claim 16, further comprising flushing a portion of the active data set based upon a replacement policy.

27. An article of manufacture, comprising:

a machine-readable medium having stored thereon instructions to;

receive a request for an object from a client;

if each data block in the requested object is in the cache, then send the requested object to the client;

if a data block in the requested object is missing, then fetch the data block from a server, filling the data block in a hierarchical relationship and as part of an active data set, and sending the requested object to the client.

28. An apparatus for caching data in a network, the apparatus comprising:

means for receiving a request for an object from a client;

coupled to the receiving means, means for sending the requested object to the client, if each data block in the requested object is in the cache;

coupled to the receiving means, means for fetching the data block from a server, for filling the data block in a hierarchical relationship and as part of an active data set, and for sending the requested object to the client, if a data block in the requested object is missing.

29. An apparatus for caching data in a network, the apparatus comprising:

a proxy cache configured to receive request for an object from a client and to fetch data blocks from a server;

the proxy cache configured to cache the data blocks in a hierarchical relationship within the object and as an active data set which is defined based upon a request from a client.

30. The apparatus of claim 29, wherein the active data set is modified by use of a data replacement strategy.

31. The apparatus of claim 29, wherein the data replacement strategy comprises one of:

a first-in-first-out method, a lease-recently-used method;

a data importance method, or a data replacement method based upon a user input.

32. The apparatus of claim 29, wherein the active data set is available to at least another client that is coupled to the proxy cache in order to permit collaborative sharing of the active data set for all clients coupled to the proxy cache.

33. The apparatus of claim 29, wherein the proxy cache is configured to translate a file handle to indicate that the file handle maps to a particular server.

34. The apparatus of claim 29, wherein the file handle is translated by use of a hash algorithm based upon a file system identifier and a server Internet Protocol address.

35. A method for caching data in a network, the method comprising:

receiving request for an object from a client;

determining if at least one data block in the requested object is stored in a cache; and

if each data block in the requested object is in the cache, then sending the requested object to the client;

if a data block in the requested object is missing, then fetching the data block from a server, allocating the data block in the cache, and sending the requested object to the client.

36. The method of claim 35, wherein the each data block is in a hierarchical relationship within an object.

37. The method of claim 35, wherein the active data set comprises a portion of data stored in at least the server.

38. The method of claim 35, wherein the active data set is defined by a particular time period.

39. The method of claim 35, wherein the request for the object is transmitted by use of an open standard protocol.

40. The method of claim 39, wherein the protocol comprises an Internet Protocol.

41. The method of claim 40, wherein the protocol comprises Network File System (NFS) protocol.

42. The method of claim 40, wherein the protocol comprises Common Internet File System (CIFS) protocol.

43. The method of claim 35, further comprising computing a unique name as part of a computation to determine the presence or absence of a data block in a data file requested by a client.

44. The method of claim 35, further comprising flushing a portion of the active data set based upon a replacement policy.

45. The method of claim 44, wherein the data replacement strategy comprises one of:

a first-in-first-out method, a lease-recently-used method;

a data importance method, or a data replacement method based upon a user input.

46. The method of claim 35, wherein the active data set is available to at least another client in order to permit collaborative sharing of the active data set for all clients that can access the active data set.

47. The method of claim 35, wherein the proxy cache is configured to translate a file handle to indicate that the file handle maps to a particular server.

48. The method of claim 47, wherein the file handle is translated by use of a hash algorithm based upon a file system identifier and a server Internet Protocol address.