Accelerating internet small computer system interface (iSCSI) proxy input/output (I/O)

• US 20100161843A1
• Filed: 12/19/2008
• Published: 06/24/2010
• Est. Priority Date: 12/19/2008
• Status: Active Grant

• Current Assignee: NetApp, Inc.
• Original Assignee: NetApp, Inc.
• Inventors: Spry, Andrew J.
• Granted Patent: US 8,892,789 B2
• Time in Patent Office: Days
• US Class Current: 710/22
• CPC Class Codes: G06F 3/0608 Saving storage space on storage systems
• CPC Class Codes: G06F 3/0655 Vertical data movement, i.e. input-output transfer; data movement between one or more hosts and one or more storage devices
• 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 67/1097 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]

Abstract

The present invention is a method for accelerating proxy Input/Output (proxy I/O). The method includes the step of receiving a command at a primary target storage system. The primary target storage system may be part of a clustered storage array. The command may be a command which was transmitted by an initiator system via a storage area network, and may include a request for data. The method further includes the step of forwarding the command to a session layer of the primary target storage system. Further, when a virtualization layer of the primary target storage system determines that a portion of the data requested in the data request is not stored by the primary target storage system, but is stored by a proxy target storage system included in the plurality of storage systems, the method further includes providing a proxyIO request to a proxy initiator of the primary target storage system. Further, the method may further include, based on the proxyIO request, generating a proxyDataIn request and providing the proxyDataIn request to an I/O controller for the primary target storage system.

Claims

1. A method for accelerating proxy Input/Output (proxy I/O), comprising:

receiving a command at a primary target storage system included in a plurality of storage systems of a clustered storage array, the command being transmitted by an initiator system to the primary target storage system via a storage area network, the command including a request for data;

forwarding the command to a session layer of the primary target storage system;

when a virtualization layer of the primary target storage system determines that a portion of the data requested in the data request is not stored by the primary target storage system, but is stored by a proxy target storage system included in the plurality of storage systems, providing a proxyIO request to a proxy initiator of the primary target storage system; and

based on the proxyIO request, generating a proxyDataIn request and providing the proxyDataIn request to an I/O controller for the primary target storage system.

2. A method as claimed in claim 1, further comprising:

based on the proxyDataIn request, creating a command context via the primary target storage system I/O controller, said command context being indexed by proxy task ID.

3. A method as claimed in claim 2, further comprising:

creating a Small Computer Systems Interface (SCSI) command via the primary target storage system I/O controller, said SCSI command including a proxy SCSI request for said portion of the data.

4. A method as claimed in claim 3, further comprising:

transmitting the SCSI command from the primary target storage system I/O controller to the proxy target storage system.

5. A method as claimed in claim 4, further comprising:

receiving the SCSI command at the proxy target storage system and forwarding said SCSI command to a SCSI layer of the proxy target storage system.

6. A method as claimed in claim 5, further comprising:

retrieving said portion of the data requested in the proxy SCSI request of the SCSI command.

7. A method as claimed in claim 6, further comprising:

providing a list of buffers containing said portion of the requested data via the SCSI layer of the proxy target storage system.

8. A method as claimed in claim 7, further comprising:

providing a sendDataIn operation from the SCSI layer of the proxy target storage system to an internet SCSI (iSCSI) layer of the proxy target storage system.

9. A method as claimed in claim 8, further comprising:

providing a dataIn operation from an iSCSI session layer of the proxy target storage system to a connection layer of an I/O controller of the proxy target storage system, said dataIn operation including the list of buffers.

10. A method as claimed in claim 9, further comprising:

generating an iSCSI Data-In Protocol Distribution Unit (iSCSI Data-In PDU) via the I/O controller of the proxy target storage system.

11. A method as claimed in claim 10, further comprising:

transmitting the iSCSI Data-In PDU from the proxy target storage system to the proxy initiator of the primary target storage system, the iSCSI Data-In PDU including said portion of the requested data.

12. A method as claimed in claim 11, further comprising:

setting an Logical Unit Number (LUN) value and a task ID value included in the iSCSI Data-In PDU to same values as an LUN and a task ID included in the initiator system command.

13. A method as claimed in claim 12, further comprising:

supplying iSCSI sequence numbers to the iSCSI Data-In PDU, said sequence numbers associated with a primary session.

14. A method as claimed in claim 13, further comprising:

routing the iSCSI Data-In PDU to a connection of the primary session.

15. A method as claimed in claim 14, further comprising:

transmitting the iSCSI Data-In PDU to the initiator system.

16. A method as claimed in claim 15, further comprising:

providing a dataInComplete event from the I/O controller of the proxy target storage system to the iSCSI layer of the proxy target storage system.

17. A method as claimed in claim 16, further comprising:

providing a sendDataInComplete event from the iSCSI layer of the proxy target storage system to the SCSI layer of the proxy target storage system;

sending a SCSI command completed event and status information from the SCSI layer of the proxy target storage system to the iSCSI layer of the proxy target storage system; and

when a SCSI command status is not sent with the iSCSI Data-In PDU, providing an SCSI Command Response type iSCSI PDU to the proxy initiator of the primary target storage system.

18. A method as claimed in claim 17, further comprising:

when the SCSI Command Response type iSCSI PDU is received by the primary target storage system from the proxy target storage system, sending a proxyDataInComplete event from the I/O controller of the primary target storage system to an iSCSI session layer of the proxy initiator, the proxyDataInComplete event including a proxy I/O data transfer status;

sending a proxyIOComplete event to the primary target storage system; and

providing a SCSI Response type iSCSI PDU to the initiator system.

19. A computer-readable medium having computer-executable instructions for performing a method for accelerating proxy Input/Output (proxy I/O), said method comprising:

receiving a command at a primary target storage system included in a plurality of storage systems of a clustered storage array, the command being transmitted by an initiator system to the primary target storage system via a storage area network, the command including a request for data;

forwarding the command to a session layer of the primary target storage system;

when a virtualization layer of the primary target storage system determines that a portion of the data requested in the data request is not stored by the primary target storage system, but is stored by a proxy target storage system included in the plurality of storage systems, providing a proxyIO request to a proxy initiator of the primary target storage system; and

based on the proxyIO request, generating a proxyDataIn request and providing the proxyDataIn request to an I/O controller for the primary target storage system.

20. A system, comprising:

means for receiving a command at a primary target storage system included in a plurality of storage systems of a clustered storage array, the command being transmitted by an initiator system to the primary target storage system via a storage area network, the command including a request for data;

means for forwarding the command to a session layer of the primary target storage system;

when a virtualization layer of the primary target storage system determines that a portion of the data requested in the data request is not stored by the primary target storage system, but is stored by a proxy target storage system included in the plurality of storage systems, means for providing a proxyIO request to a proxy initiator of the primary target storage system; and

based on the proxyIO request, means for generating a proxyDataIn request and providing the proxyDataIn request to an I/O controller for the primary target storage system.