Non-disruptive storage caching using spliced cache appliances with packet inspection intelligence

• US 20090182835A1
• Filed: 01/16/2008
• Published: 07/16/2009
• Est. Priority Date: 01/16/2008
• Status: Active Grant

• Current Assignee: NetApp, Inc.
• Original Assignee: NetApp, Inc.
• Inventors: Aviles, Joaquin J., Cree, Mark U., Dahl, Gregory A.
• Granted Patent: US 9,143,566 B2
• Time in Patent Office: Days
• US Class Current: 709/213
• CPC Class Codes: G06F 12/0813 with a network or matrix configuration
• CPC Class Codes: G06F 12/0866 for peripheral storage systems, e.g. disk cache
• CPC Class Codes: G06F 12/123 with age lists, e.g. queue, most recently used [MRU] list or least recently used [LRU] list
• CPC Class Codes: G06F 3/0611 in relation to response time
• CPC Class Codes: H04L 67/1097 for distributed storage of data in networks, e.g. transport arrangements for network file system [NFS], storage area networks [SAN] or network attached storage [NAS]
• CPC Class Codes: H04L 67/56 Provisioning of proxy services store-and-forward switching systems in data switching networks H04L12/54
• CPC Class Codes: H04L 67/5682 Policies or rules for updating, deleting or replacing the stored data

Abstract

A method, system and program are disclosed for accelerating data storage by providing non-disruptive storage caching using spliced cache appliances with packet inspection intelligence. A cache appliance that transparently monitors NFS and CIFS traffic between clients and NAS subsystems and caches files using dynamically adjustable cache policies provides low-latency access and redundancy in responding to both read and write requests for cached files, thereby improving access time to the data stored on the disk-based NAS filer (group).

Claims

1. A standalone cache unit for caching data operations requested from one or more networked data storage devices by one or more remote clients, the cache unit comprising:

a cache memory for caching data that is requested by a remote client;

a high-speed packet processor coupled to the cache memory and to one or more I/O ports for splicing connections between the data storage devices and remote clients, where the high-speed packet processor inspects network protocol traffic state parameters received on the I/O ports to determine if a request from a remote client can be serviced by the cache memory.

2. The standalone cache unit of claim 1, further comprising a network switch interconnect coupled between the one or more I/O ports, the high-speed packet processor and the cache memory for routing network protocol traffic from the data storage devices and remote clients.

3. The standalone cache unit of claim 1, further comprising a cache controller coupled to the cache memory for servicing read and write requests from a remote client with data stored on cache memory.

4. The standalone cache unit of claim 1, where the high-speed packet processor executes software that transparently monitors NFS and CIFS traffic between remote clients and NAS subsystems and caches files using a predetermined cache policy.

5. The standalone cache unit of claim 4, where the predetermined cache policy comprises a least recently used with dual time reference algorithm aided with greedy dual size frequency algorithm.

6. The standalone cache unit of claim 1, where the high-speed packet processor splices connections between the data storage devices and remote clients by splicing only a part of a TCP/IP layer stack defining a connection.

7. The standalone cache unit of claim 1, where the high-speed packet processor splices connections between the data storage devices and remote clients so as to be transparent to L3 and L4 network layers defining a connection.

8. The standalone cache unit of claim 1, where the standalone cache unit is connected in-line between the remote clients and the one or more networked data storage devices so as to intercept all data operation requests submitted to the one or more networked data storage devices.

9. A method for caching data operations, comprising:

receiving at a standalone cache unit a request from a remote client to perform a specified data operation at one or more networked data storage devices;

inspecting packet parameters in each TCP/IP stack layer associated with the request to determine if the request can be serviced by a cache memory located at the standalone cache unit;

forwarding the request to the one or more networked data storage devices if the request can not be serviced by the cache memory located at the standalone cache unit; and

performing the specified data operation at the cache memory located at the standalone cache unit if the request can be serviced by the cache memory located at the standalone cache unit.

10. The method of claim 9, further comprising splicing connections between the remote client and the one or more networked data storage devices.

11. The method of claim 10, where splicing connections comprises splicing some, but not all, of all of the packet parameters in the TCP/IP stack so as to be transparent to the client and the one or more networked data storage devices.

12. The method of claim 10, where splicing connections comprises splicing connections between the one or more networked data storage devices and the remote client so as to be transparent to L3 and L4 network layers defining a connection.

13. The method of claim 10, where splicing connections comprises splicing only a connection state, a source sequence number and a destination sequence number in an L4 layer.

14. The method of claim 10, where performing the specified data operation at the cache memory comprises caching files in the cache memory using a predetermined cache policy.

15. The method of claim 14, where the predetermined cache policy comprises a least recently used with dual time reference algorithm aided with greedy dual size frequency algorithm.

16. The method of claim 9, where inspecting packet parameters comprises transparently monitoring NFS and CIFS traffic between the remote client and the one or more networked data storage devices.

17. The method of claim 9, further comprising caching files in the cache memory located at the standalone cache unit using dynamically adjustable cache policies that reflect application workloads that change over time.

18. A network cache appliance for accelerating read and write requests from one or more storage clients for one or more files residing at one or more networked storage devices, comprising:

a tiered memory cache system for providing low-latency access in responding to read and write requests comprising a first cache storage for storing business critical data under control of a policy engine that is managed independently from the one or more networked storage devices; and

a packet inspection module for inspecting a read or write request sent using an IP-based network protocol to determine if the request should be passed to the tiered memory cache system or forwarded to a networked storage device for further processing.

19. The network cache appliance of claim 18, where the tiered memory cache system comprises:

a dynamic and non-volatile cache memory for providing low-latency access in responding to read and write requests; and

a cache controller for caching files in the cache memory using a predetermined cache policy.

20. The network cache appliance of claim 18, where the packet inspection module comprises:

a packet processor coupled to the tiered memory cache system; and

a network switch interconnect coupled between the one or more I/O ports, the packet processor and the tiered memory cache system for routing network protocol traffic between the one or more storage clients and the one or more networked storage devices.

21. The network cache appliance of claim 18, where the packet inspection module is capable of accepting user-specified cache profile to provide preferential access to the cache memory for files from a user-specified application data set according to a predetermined set of pattern searching and/or content matching.