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

• US 8,073,899 B2
• Filed: 04/29/2005
• Issued: 12/06/2011
• Est. Priority Date: 04/29/2005
• Status: Active Grant

• Current Assignee: NetApp, Inc.
• Original Assignee: NetApp, Inc.
• Inventors: Grier, James R., Rajan, Vijayan, Meneghini, John, Lent, Arthur F.
• Primary Examiner(s): DWIVEDI, MAHESH H
• Application Number:
  US11/118,299
• Publication Number:
  US 20060248047A1
• Time in Patent Office: 2,412 Days
• Field of Search: 714/6, 709/201, 709/203
• US Class Current: 709/203
• 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 over a cluster interconnect to a second storage system in a storage system cluster, comprising:

receiving, from a client operatively connected to the cluster, a block-level data access command at the first storage system that is directed to a file on the second storage system, wherein the block-level data access command comprises a world wide port name (WWPN) and a logical unit number (lun) identifier;

transforming at the first storage system the received block-level data access command to a file-level data access request by mapping the WWPN and lun identifier to a file handle associated with the file;

forwarding the file-level data access request including the file handle from the first storage system to the second storage system over the cluster interconnect;

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

generating a file-level response at the second storage system in response to processing the file-level data access request; and

returning the file-level response from the second storage system to the first storage system over the cluster interconnect.

2. The method of claim 1 wherein the received data access command is received at a proxy port associated with the first storage system.

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 cluster interconnect comprises an Ethernet based cluster interconnect.

10. The method of claim 1 further comprising:

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 request comprises a file-level write operation.

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

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

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

15. A method for proxying data access commands from a first storage system over a cluster interconnect to a second storage system in a storage system cluster, comprising:

analyzing a received block-level data access command at the first storage system that is directed to a data container on the second storage system, the block-level data access command received from a client operatively connected to the storage system cluster;

transforming at the first storage system the received block-level data access command to a file-level data access command by mapping the block-level data access command to a file handle associated with the data container;

forwarding the file-level data access command including the file handle from the first storage system to the second storage system over the cluster interconnect; and

processing the file-level data access command for the data container at the second storage system using the file handle.

16. The method of claim 15 further comprising:

generating and returning a first response from the second storage system to the first storage system in response to processing the file-level data access command; and

sending a second response to the data access command to the client from the first storage system, wherein the second response comprises data associated with the data access command that is mapped to a block-level protocol of the block-level data access command utilized by the client if the received block-level data access command is a read command, and wherein the second response comprises an acknowledgement if the received block-level data access command is a write command.

17. The method of claim 15 wherein the cluster interconnect comprises an Ethernet based cluster interconnect.

18. The method of claim 15 wherein the cluster interconnect comprises a fibre channel link.

19. The method of claim 17 wherein the cluster interconnect comprises a direct link between the first storage system and the second storage system.

20. The method of claim 15 further comprising receiving the data access command at a proxy port of the first storage system.

21. The method of claim 20 wherein the proxy port comprises a physical port.

22. The method of claim 20 wherein the proxy port comprises a virtual port associated with a physical port.

23. The method of claim 16 wherein the second response comprises requested read data.

24. The method of claim 16 wherein the second response comprises an acknowledgement of a write operation.

25. A computer readable medium containing executable program instructions executable by a processor, comprising:

program instructions that analyze a received block-level data access command at a first storage system that is directed to a data container on a second storage system;

program instructions that transform at the first storage system the received block-level data access command to a file-level data access command by mapping the block-level data access command to a file handle associated with the data container;

program instructions that forward the file-level data access command including the file handle from the first storage system to the second storage system over a cluster interconnect; and

program instructions that process the file-level data access command for the data container at the second storage system.

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

means for analyzing a block-level received data access command at the first storage system that is directed to a data container on the second storage system, the block-level data access command received from a client operatively connected to the storage system cluster;

means for transforming at the first storage system the received block-level data access command to a file-level data access command by mapping the block-level data access command to a file handle associated with the data container;

means for forwarding the file-level data access command including the file handle from the first storage system to the second storage system over the cluster interconnect; and

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

27. The system of claim 26 wherein the received data access command is received at a proxy port associated with the first storage system.

28. The system of claim 27 wherein the proxy port comprises a physical port.

29. The system of claim 27 wherein the proxy port comprises a virtual port associated with a physical port.

30. A method for proxying data access commands from a first storage system over a cluster interconnect to a second storage system in a storage system cluster, comprising:

configuring a proxy port on the first storage system, wherein the proxy port is an alternative network path to the second storage system;

receiving a block-level data access command at the proxy port, wherein the block-level data access command is directed to a data container on the second storage system, and wherein the block-level data access command comprises a world wide port name (WWPN) and a logical unit number (lun) identifier;

transforming at the first storage system the received block-level data access command to a file-level data access request by mapping the WWPN and lun identifier to a file handle that identifies the data container embodying the lun to which the received block-level request is directed;

forwarding the file-level data access request including the file handle over the cluster interconnect from the first storage system to the second storage system;

processing the file-level data access request for the data container at the second storage system using the file handle;

generating a file-level response at the second storage system in response to processing the file-level data access request; and

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

31. The method of claim 30, wherein the proxy port comprises a physical port.

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

33. The method of claim 30, wherein the file-level response comprises requested read data and a predetermined set of read data.

34. The method of claim 30, wherein the file-level response comprises an acknowledgement of a write operation.

35. The method of claim 30, wherein the cluster interconnect comprises a direct link between the first storage system and the second storage system.

36. The method of claim 30, further comprising:

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.

37. The method of claim 30, wherein the file-level data access request comprises a file-level write operation comprising the file handle, an offset, and a set of data to be written.

38. The method of claim 30, wherein the file-level data access request comprises a file-level read operation comprising the file handle, an offset, and a number of blocks to be read.

39. A system for proxying data access commands in a storage system cluster, comprising:

a first storage system configured to be operatively connected to a second storage system via a cluster interconnect;

the first storage system configured to receive, from a client operatively connected to the storage system cluster, a block-level data access command that is directed to a data container on the second storage system;

the first storage system further configured to transform the received block-level data access command to a file-level data access request, wherein the first storage system is further configured to map the block-level data access command to a file handle associated with the data container to generate the file-level data access request;

the first storage system further configured to forward the file-level data access request including the file handle from the first storage system to the second storage system over the cluster interconnect; and

the first storage system further configured to receive a file-level response from the second storage system in response to the second storage system processing the file-level data access request, the first storage system further to return a client response to the client in response to receiving the file-level response from the second storage system.

40. The system of claim 39 wherein the data access command is received at a proxy port of the first storage system.

41. The system of claim 40 wherein the proxy port comprises a physical port.

42. The system of claim 40 wherein the proxy port comprises a virtual port associated with a physical port.