Network caching device including translation mechanism to provide indirection between client-side object handles and server-side object handles

• US 7,631,078 B2
• Filed: 01/16/2007
• Issued: 12/08/2009
• Est. Priority Date: 09/16/2002
• Status: Active Grant

• Current Assignee: NetApp, Inc.
• Original Assignee: NetApp, Inc.
• Inventors: Amdur, Matthew, Grunwald, David, Ayyar, Kartik, Prakash, Ashish, Ackaouy, Emmanuel, Quirion, Brian
• Primary Examiner(s): BOUTAH, ALINA A
• Application Number:
  US11/654,381
• Publication Number:
  US 20070192444A1
• Time in Patent Office: 1,057 Days
• Field of Search: 709/219, 709/225, 709/202, 709213-216, 709/231, 707/10, 711/122, 711/218, 711/119, 710/10
• 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. A method comprising:

caching, in a network caching device on a network, objects that originate from a plurality of origin servers;

receiving at the network caching device requests for various ones of the objects from a plurality of clients; and

using a translation mechanism in the network caching device to service the requests, the translation mechanism establishing a layer of indirection between client-side handles used by the clients to request the objects and server-side handles corresponding to said objects, wherein using the translation mechanism includes using a file handle mapping in the network caching device to translate a client-side file handle to a server-side file handle used by an origin server that stores an object, the mapping being based on a hash which is a function of an address of the origin server and at least a portion of the server-side file handle.

2. A method as recited in claim 1, wherein using the translation mechanism comprises making identities of origin servers from which the objects originate transparent to the clients.

3. A method as recited in claim 1, wherein using the translation mechanism comprises enabling a client to access a plurality of mount points through a single client-side handle.

4. A method as recited in claim 1, wherein using the translation mechanism comprises enabling access to a particular object with a plurality of different sets of export options.

5. A method as recited in claim 4, wherein enabling access to a particular object with a plurality of different sets of export options comprises associating a server-side handle for the particular object with a plurality of different client-side handles, each having a different set of export options.

6. A method as recited in claim 1, wherein the hash further is at least partially based on a file system identifier and a file name corresponding to the object.

7. A method as recited in claim 1, wherein each of the objects comprises a plurality of blocks in a hierarchical relationship.

8. A method comprising:

receiving from a client, at a network caching device on a network, a request for an object, the request including a client-side file handle;

determining that a cache miss has occurred by determining that at least a portion of the object is not stored in the network caching device;

in response to determining that the cache miss has occurred,

using a file handle mapping in the network caching device to translate the client-side file handle to a server-side file handle used by an origin server that stores the object, the mapping being based on a hash which is a function of an address of the origin server and at least a portion of the server-side file handle; and

using the server-side file handle to retrieve at least a portion of the object not stored in the network caching device from the server; and

providing the object to the client in response to the request.

9. A method as recited in claim 8, wherein the hash is a function of a server-side file system identifier of the object.

10. A method as recited in claim 9, wherein the hash further is a function of a file name of the object.

11. A method as recited in claim 8, wherein the mapping makes the identity of the origin server transparent to the client.

12. A method as recited in claim 8, further comprising using the mapping to enable the client to access a plurality of mount points through the client-side file handle.

13. A method as recited in claim 8, further comprising using the mapping to enable the client to access the object with a plurality of different sets of export options.

14. A method as recited in claim 13, wherein using the mapping to enable the client to access the object with a plurality of different sets of export options comprises associating the server-side file handle for the particular object with a plurality of different client-side file handles, each having a different set of export options.

15. A method as recited in claim 8, wherein the object comprises a plurality of blocks in a hierarchical relationship.

16. A machine-readable storage medium storing code which, when executed by a machine, causes the machine to perform a process comprising:

caching, in a network caching device on a network, an object that originates from an origin server;

receiving at the network caching device a request for the object from a client; and

using a translation mechanism in the network caching device to service the request, the translation mechanism establishing a layer of indirection between a client-side handle used by the client to request the object and server-side handle corresponding to the object, wherein using the translation mechanism includes using a file handle mapping in the network caching device to translate a client-side file handle to a server-side file handle used by an origin server that stores an object, the mapping being based on a hash which is a function of an address of the origin server and at least a portion of the server-side file handle.

17. A machine-readable storage medium as recited in claim 16, wherein using the translation mechanism comprises making an identity of the origin server transparent to the client.

18. A machine-readable storage medium as recited in claim 16, wherein using the translation mechanism comprises enabling the client to access a plurality of mount points through the client-side handle.

19. A machine-readable storage medium as recited in claim 16, wherein using the translation mechanism comprises enabling access to the object with a plurality of different sets of export options.

20. A machine-readable storage medium as recited in claim 19, wherein enabling access to the object with a plurality of different sets of export options comprises associating a server-side handle for the particular object with a plurality of different client-side handles, each having a different set of export options.

21. A machine-readable storage medium as recited in claim 16, wherein the hash further is at least partially based on a file system identifier and a file name corresponding to the object.

22. A machine-readable storage medium as recited in claim 16, wherein the object comprises a plurality of blocks in a hierarchical relationship.

23. An apparatus comprising:

a proxy cache configured to receive from a client a request for an object over a network, the request including a client-side handle;

the proxy cache further configured to respond to a determination that a cache miss has occurred in relation to the request by

using a mapping in the proxy cache to translate the client-side handle to a server-side handle used by an origin server that stores the object, the mapping being based on a hash which is a function of an address of the origin server and at least a portion of the server-side handle; and

using the server-side handle to retrieve at least a portion of the object not stored in the proxy cache from the server; and

the proxy cache further configured to provide the object to the client in response to the request.

24. An apparatus as recited in claim 23, wherein the hash is a function of a server-side file system identifier of the object.

25. An apparatus as recited in claim 24, wherein the hash further is a function of a file name of the object.

26. An apparatus as recited in claim 23, wherein the mapping makes the identity of the origin server transparent to the client.

27. An apparatus as recited in claim 23, wherein the proxy cache is further configured to use the mapping to enable the client to access a plurality of mount points through the client-side file handle.

28. An apparatus as recited in claim 23, wherein the proxy cache is further configured to use the mapping to enable the client to access the object with a plurality of different sets of export options.

29. An apparatus as recited in claim 28, wherein use of the mapping to enable the client to access the object with a plurality of different sets of export options comprises associating the server-side file handle for the particular object with a plurality of different client-side file handles, each having a different set of export options.

30. An apparatus as recited in claim 23, wherein the object comprises a plurality of blocks in a hierarchical relationship.