System and method for proxying data access commands in a storage system cluster

• US 20060248047A1
• Filed: 04/29/2005
• Published: 11/02/2006
• Est. Priority Date: 04/29/2005
• Status: Active Grant

• Current Assignee: NetApp, Inc.
• Original Assignee: NetApp, Inc.
• Inventors: Rajan, Vijayan, Lent, Arthur F., Meneghini, John, Grier, James R.
• Granted Patent: US 8,073,899 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 3/0607 by facilitating the process of upgrading existing storage systems, e.g. for improving compatibility between host and storage device
• CPC Class Codes: G06F 3/0635 by changing the path, e.g. traffic rerouting, path reconfiguration
• CPC Class Codes: G06F 3/067 Distributed or networked storage systems, e.g. storage area networks [SAN], network attached storage [NAS]
• CPC Class Codes: H04L 67/06 specially adapted for file transfer, e.g. file transfer protocol [FTP]
• 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 67/2895 Intermediate processing functionally located close to the data provider application, e.g. reverse proxies
• 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 67/59 Providing operational support to end devices by off-loading in the network or by emulation, e.g. when they are unavailable

Abstract

A system and method proxies data access commands acrossed a cluster interconnect between storage appliances and a cluster using a file-level protocol. Each storage appliance activates two ports per data access, a local port for data access requests directed to clients of the storage appliance and a proxy port for data access requests directed to the partner storage appliance. Clients utilizing multi-pathing software may send data access requests to either the local port of the storage appliance or the proxy port of the storage appliance. The system and method improves high availability, especially during a loss of connectivity due to non-storage appliance hardware failure.

Claims

1. A method for proxying data access commands from a first storage system to a second storage system in a storage system cluster, the method comprising the steps of:

receiving a data access command at the first storage system that is directed to the second storage system;

generating a file-level data access request from the received data access command;

forwarding the file-level data access request to the second storage system;

processing the file-level data access request at the second storage system; and

returning a file-level response from the second storage system to the first storage system;

2. The method of claim 1 wherein the storage systems are storage appliances and wherein the data access command is received at a proxy port associated with the first storage appliance.

3. The method of claim 2 wherein the proxy port comprises a physical port.

4. The method of claim 2 wherein the proxy port comprises a virtual port associated with a physical port.

5. The method of claim 1 wherein the file-level response comprises requested read data.

6. The method of claim 1 wherein the file-level response comprises an acknowledgement of a write operation.

7. The method of claim 1 wherein the file-level response comprises a predetermined set of read data.

8. The method of claim 1 wherein the cluster interconnect comprises a direct link between the first storage system and the second storage system.

9. The method of claim 1 wherein the file-level data access request is forwarded to the second storage system via a cluster interconnect.

10. The method of claim 1 further comprising the steps of:

generating a client response from the file-level response; and

sending the client response to the data access command to the client from the first storage system

11. The method of claim 1 wherein the file-level data access operation request comprises a file-level write operation.

12. The method of claim 11 wherein the file-level write operation comprises a file handle, an offset, and a set of data to be written.

13. The method of claim 1 wherein the file-level data access operation comprises a file-level read operation.

14. The method of claim 13 wherein the file-level read operation comprises a file handle, an offset and a number of blocks to be read.

19. The storage appliance of claim 14 wherein the storage operating system further comprising a virtual adapter that interfaces with the virtual target module and an interconnect driver for forwarding the file-level data access operations from the virtual target module to the partner storage appliance via a cluster interconnect managed by the interconnect driver.

20. The storage appliance of claim 19 wherein the cluster interconnect comprises a fibre channel interconnect.

21. The storage appliance of claim 19 wherein the cluster interconnect directly connects the storage appliance to the partner storage appliance.

15. A system adapted to proxy data access commands from a first storage system to a second storage system connected via a cluster interconnect, the system comprising:

a virtual target layer interfacing with a virtual adapter on the first storage system, the virtual target module adapted to make a forwarding decision of a received data access request to thereby forward the request to the second storage system.

16. The system of claim 15 wherein the forwarding decision is based on a port to which the data access request is directed.

17. The system of claim 16 wherein the forwarding decision is based upon a logical unit address contained within the data access request.

18. A storage appliance for use in a storage appliance cluster for proxying data access commands received at the storage appliance to a partner storage appliance in a storage appliance cluster, the storage appliance comprising:

a storage operating system executing on the storage appliance, the storage operating system including a virtual target module adapted to generate file-level data access operations from received data access operations, the file-level data access operations directed to a file located on the partner storage appliance.

22. The storage appliance of claim 18 wherein the virtual adapter interfaces with a virtual target module to present an adapter interface.

23. A method for proxying data access commands in the first storage system to a second system in a storage system cluster, the method comprising the steps of:

analyzing a received data access command at the first storage system;

generating a file-level data access command from the received data access command;

forwarding the file-level data access command to the second storage system; and

processing the file-level data access command at the second storage system.

24. The method of claim 23 further comprising the steps of;

returning a response from the second storage system to the first storage system; and

sending a response to the data access command to the client from the first storage system.

25. The method of claim 23 wherein the step of forwarding further comprises the step of forwarding the data access command to the second storage system via a cluster interconnect.

26. The method of claim 23 wherein the cluster interconnect comprises a fibre channel link.

27. The method of claim 25 wherein the cluster interconnect comprises a direct link between the first storage system and the second storage system.

28. The method of claim 23 further comprising the step of receiving the data access command is at a proxy port of the first storage system.

29. The method of claim 28 wherein the proxy port comprises a physical port.

30. The method of claim 28 wherein the proxy port comprises a virtual port associated with the physical port.

31. The method of claim 24 wherein the response comprises requested read data.

32. The method of claim 24 wherein the response comprises an acknowledgement of the write operation.

33. A computer readable medium, including program instructions executing on a computer, for proxying data access commands from a first storage system to a second storage system in a storage system cluster, the computer readable medium including instructions for performing the steps of:

analyzing a received data access command at the first storage system;

generating a file-level data access command from the received data access command;

forwarding the file-level data access command to the second storage system; and

processing the file-level data access command at the second storage system.

34. A system for proxying data access commands from a first storage system to a second storage system connected via a cluster interconnect, the system comprising:

means for analyzing a received data access command at the first storage system;

means for generating a file-level data access command from the received data access command;

means for forwarding the file-level data access command to the second storage system; and

means for processing the file-level data access command at the second storage system.

35. The method of claim 34 wherein storage systems are storage appliances and the data access command is received at a proxy port associated with the first storage appliance.

36. The method of claim 35 wherein the proxy port comprises a physical port.

37. The method of claim 35 wherein the proxy port comprises a virtual port associated with a physical port.