SYSTEM AND METHOD FOR OPERATING A SYSTEM TO CACHE A NETWORKED FILE SYSTEM

• US 20140082288A1
• Filed: 09/18/2013
• Published: 03/20/2014
• Est. Priority Date: 09/18/2012
• Status: Active Grant

• Current Assignee: NetApp, Inc.
• Original Assignee: NetApp, Inc.
• Inventors: Beard, Derek, Yammine, Ghassan, Dahl, Gregory
• Granted Patent: US 9,355,036 B2
• Time in Patent Office: Days
• US Class Current: 711/123
• CPC Class Codes: G06F 12/0875 with dedicated cache, e.g. instruction or stack
• CPC Class Codes: G06F 16/172 Caching, prefetching or hoarding of files
• CPC Class Codes: G06F 3/0611 in relation to response time
• CPC Class Codes: G06F 3/0646 Horizontal data movement in storage systems, i.e. moving data in between storage devices or systems
• CPC Class Codes: G06F 3/0671 In-line storage system

Abstract

A network attached storage (NAS) caching appliance, system, and associated method of operation for caching a networked file system. Still further, some embodiments provide for a cache system that implements a mufti-tiered, policy-influenced block replacement algorithm.

Claims

1. A computer-readable medium that stores instructions for caching a networked file system, the instructions being executable by one or more processors to cause the one or more processors to perform operations comprising:

connecting a cache system in-line as between a networked file system and one or more clients of the networked file system, the cache system including one or more appliances that store data corresponding to at least a portion of the networked file system;

processing requests from the one or more clients for application data provided by the networked file system;

wherein processing the requests includes determining whether individual requests specify data from the networked file system that are also stored in the cache system;

wherein for each processed request that specifies data stored in the cache system, providing a response to that request using data that is stored in the cache system;

wherein for each processed request that specifies data that is not stored with the cache system,

forwarding the request to the networked file system for a response,

processing the response from the networked file system, including caching data corresponding to a file system object returned with the response from the networked file system, and

forwarding the response from the networked file system to a client from which that request originated.

2. The computer-readable medium of claim 1, wherein instructions for caching data returned with the response include instructions for:

identifying multiple cache resources that cache data corresponding to at least a portion of the networked file system;

identifying a rank of each of the multiple cache resources;

assigning a rank to the cached data, the rank indicating one of the multiple cache resources where the cached data is to be located.

3. The computer-readable medium of claim 2, wherein instructions for assigning the rank to the cached data includes determining the rank based at least in part on an access count of the file system object corresponding to the data returned with the response.

4. The computer-readable medium of claim 1, wherein instructions for caching data returned with the response from the networked file system includes instructions for:

identifying multiple cache resources that cache data corresponding to at least a portion of the networked file system;

identifying a rank of each of the multiple cache resources, the rank indicating one of the multiple cache resources where the cached data is to be located;

determining a highest rank cache resource that has available space to store the data returned with the response.

5. The computer-readable medium of claim 4, further comprising instructions for assigning a rank for the cached data, wherein the rank corresponds to the determined highest rank cache resource.

6. The computer-readable medium of claim 5, further comprising instructions for determining which of the multiple cache resources are to store the cached data based at least in part on the assigned rank for the cached data.

7. The computer-readable medium of claim 1, wherein instructions for caching data returned with the response from the networked file system includes instructions for:

identifying multiple cache resources that cache data corresponding to at least a portion of the networked file system;

identifying a rank of each of the multiple cache resources, the rank indicating one of the multiple cache resources where the cached data is to be located;

determining a natural rank for the cached data, the natural rank being based on an access count of file system object corresponding to the data returned with the response; and

determining which of the multiple cache resources are to store the cached data based at least in part on the natural rank for the cached data and the rank of each of the multiple cache resources.

8. The computer-readable medium of claim 5, further comprising instructions for:

determining a natural rank for the cached data, the natural rank being based on an access count of file system object corresponding to the data returned with the response;

assigning the cached data to the cache resource of the highest rank if the highest rank is higher than the natural rank, else assigning the cached data to the cache resource of the natural rank.

9. The computer-readable medium of claim 2, wherein instructions for caching data returned with the response from the networked file system includes determining a priority designation for the file system object corresponding to the data returned with the response, and storing the cached data with the assigned cache resource and in accordance with the priority designation of the file system object corresponding to the data returned with the response.

10. The computer-readable medium of claim 9, wherein instructions for determining the priority designation for the file system object is based on one or more user-defined policies.

11. The computer-readable medium of claim 10, further comprising instructions for determining when to evict the cached data from the assigned cache resource based on the priority designation.

12. The computer-readable medium of claim 11, further comprising instructions for evicting the cached data from the assigned cache resource by performing one of (i) removing the cached data from the cache resource of the assigned rank and storing the cached data with a cache resource of a next lowest rank if a rank of the assigned cache resource is not a base rank, else (ii) removing the cached data from the cache resource of the assigned rank so that the cached data is no longer cached.

13. The computer-readable medium of claim 2, wherein instructions for identifying the rank of each of the multiple cache resources is based on a type of memory employed with one or more of the multiple cache resources.

14. A cache system comprising:

multiple cache resources;

one or more processors to;

connect the cache system to a networked file system, the cache system being connected in-line as between the networked file system and one or more clients of the networked file system;

process requests from the one or more clients for application data provided by the networked file system by;

(i) determining whether individual requests specify data from the networked file system that are stored in the cache system, and for each processed request that specifies data stored in the cache system, provide a response to that request using data that is stored in the cache system;

or

(ii) for each processed request that specifies data that is not stored locally in the cache system, forward the request to the networked file system for a response, process the response from the networked file system, including caching data corresponding to a file system object returned with the response from the networked file system, and forward the response from the networked file system to a client from which that request originated.

15. The cache system of claim 14, wherein the one or more processors assign a rank to each of the multiple cache resources, the rank for at least one or more of the multiple cache resources being based on a type of memory used with that cache resource.

16. The cache system of claim 15, wherein the one or more processors assign a rank to the cached data, the rank indicating which one of the multiple cache resources are to store the cached data.

17. The cache system of claim 14, wherein the one or more processors provide a policy engine that receives input for determining multiple policies, wherein the one or more processors determine a priority designation for the cached data based on one or more of the multiple policies.

18. The cache system of claim 16, wherein the one or more processors

assign a rank to each of the multiple cache resources, the rank for at least one or more of the multiple cache resources being based on a type of memory used with that cache resource;

assign a rank to the cached data, the rank indicating which one of the multiple cache resources are to store the cached data;

determine a priority designation for the file system object corresponding to the data returned with the response; and

store the cached data with the assigned cache resource and in accordance with the priority designation of the file system object corresponding to the data returned with the response.

19. The cache system of claim 18, wherein the one or more processors determine when to evict the cached data from the assigned cache resource based on the priority designation.