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

• US 9,361,042 B2
• Filed: 10/21/2014
• Issued: 06/07/2016
• Est. Priority Date: 12/19/2008
• Status: Active Grant

• Current Assignee: NetApp, Inc.
• Original Assignee: NetApp, Inc.
• Inventors: Spry, Andrew J.
• Primary Examiner(s): Tsai, Henry
• Assistant Examiner(s): BARTELS, CHRISTOPHER A.
• Application Number:
  US14/519,966
• Publication Number:
  US 20150039792A1
• Time in Patent Office: 595 Days
• Field of Search: None
• US Class Current: 1/1
• 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 (proxyI/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 including a request for data from an initiator system at a primary target storage system, the primary target storage system comprising;

a first I/O controller communicatively coupled to the initiator system; and

a second I/O controller communicatively coupled to a proxy target storage system;

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

when 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, providing a proxyDataIn request from the session layer of the primary target storage system to the second I/O controller;

using the second I/O controller, requesting the portion of the data from the proxy target storage system; and

providing, to the initiator system, a received response to the requesting, wherein the providing includes routing the response from the second I/O controller to the first I/O controller by a connection layer command.

2. The method of claim 1 wherein the requesting of the portion of the data includes:

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

3. The method of claim 2, wherein the requesting of the portion of the data further includes:

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

4. The method of claim 3, wherein the requesting of the portion of the data further includes:

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

5. The method of claim 1 further comprising, based on the proxyDataIn request, creating a command context via the second I/O controller, the command context being indexed by proxy task ID.

6. The method of claim 1, wherein the providing of the proxyDataIn request includes:

providing a proxyIO request to a proxy initiator of the primary target storage system; and

based on the proxyIO request, generating the proxyDataIn request.

7. The method of claim 1 further comprising:

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

8. The method of 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. The method of claim 8 further comprising:

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

10. The method of claim 9 further comprising:

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

11. The method of claim 1, wherein the requesting of the portion of the data includes:

receiving an iSCSI Data-In Protocol Distribution Unit (PDU) received from the proxy target storage system in response to the proxyDataIn request; and

routing the iSCSI Data-In PDU from the second I/O controller of the primary target storage system to the first I/O controller of the primary target storage system, wherein the routing is performed entirely at the connection layer.

12. The non-transitory machine readable medium of claim 11, comprising further machine executable code that causes the machine to:

receive an iSCSI Data-In Protocol Distribution Unit (PDU) from the second storage system in response to the proxyDataIn request; and

route the iSCSI Data-In PDU from the second I/O controller of the first storage system to the first I/O controller of the first storage system, wherein the routing is performed entirely at the connection layer.

13. A non-transitory machine readable medium having stored thereon instructions for performing a method for accelerating proxy Input/Output (proxy I/O), which when executed by at least one machine, causes the machine to:

receive a command from an initiator system at a first I/O controller of a first storage system, wherein the command includes a request for data;

forward the command to a session layer of the first storage system;

when the first storage system determines that a portion of the data requested in the command is not stored by the first storage system, but is stored by a second storage system to which a second I/O controller of the first storage system is communicatively coupled, provide a proxyIO request to a proxy initiator of the first storage system;

based on the proxyIO request, generate a proxyDataIn request and provide the proxyDataIn request from the session layer of the first storage system to the second I/O controller; and

request the portion of the data from the second storage system.

14. The non-transitory machine readable medium of claim 13 comprising further machine executable code that causes the machine to:

provide, to the initiator system, a received response to the requesting, wherein the providing includes routing the response from the second I/O controller to the first I/O controller by a connection layer command.

15. The non-transitory machine readable medium of claim 14, comprising further machine executable code that causes the machine to:

create a Small Computer Systems Interface (SCSI) command via the second I/O controller, the SCSI command including a proxy SCSI request for the portion of the data.

16. The non-transitory machine readable medium of claim 15, comprising further machine executable code that causes the machine to:

transmit the SCSI command from the second I/O controller to the second storage system.

17. The non-transitory machine readable medium of claim 16, comprising further machine executable code that causes the machine to:

receive the SCSI command at the second storage system and forward the SCSI command to a SCSI layer of the second storage system.

18. A storage system comprising:

a first input/output (I/O) controller communicatively coupled to an initiator via a storage area network and operable to communicate with the initiator using at least an iSCSI protocol;

a second input/output (I/O) controller communicatively coupled to a target storage system and operable to communicate with the target storage system using at least an iSCSI protocol;

a memory containing machine readable medium comprising machine executable code having stored thereon instructions for performing a method of accelerating proxy Input/Output (proxy I/O); and

at least one processor coupled to the memory, the at least one processor configured to execute the machine executable code to;

receive a command including a request for data from the initiator at the first I/O controller;

upon determining that a portion of the data requested in the data request is not stored by the storage system, provide a proxyDataIn request from a session layer of the storage system to the second I/O controller;

using the second I/O controller, request the portion of the data from the target storage system; and

provide, to the initiator, a received response by routing the response from the second I/O controller to the first I/O controller by a connection layer command.

19. The storage system of claim 18, wherein the at least one processor is further configured to execute the machine executable code to:

create a Small Computer Systems Interface (SCSI) command via the second I/O controller, wherein the SCSI command includes a proxy SCSI request for the portion of the data.

20. The storage system of claim 19, wherein the at least one processor is further configured to execute the machine executable code to:

transmit the SCSI command from the second I/O controller to the target storage system.