Method of implementing IP-based proxy server for ISCSI services

• US 8,359,379 B1
• Filed: 04/30/2008
• Issued: 01/22/2013
• Est. Priority Date: 04/30/2008
• Status: Active Grant

• Current Assignee: NetApp, Inc.
• Original Assignee: NetApp, Inc.
• Inventors: Sen, Subhabrata
• Primary Examiner(s): Lazaro, David
• Assistant Examiner(s): HUQ, FARZANA B
• Application Number:
  US12/112,745
• Time in Patent Office: 1,728 Days
• Field of Search: 709/223, 709/230, 709/238, 709/245, 709/249
• US Class Current: 709/223
• 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 61/2514 between local and global IP addresses
• 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

A facility for impersonating a number of iSCSI initiators within a IP-based Storage Area Network (SAN) is provided. In some embodiments, the facility receives iSCSI PDUs from a plurality of iSCSI devices. Each iSCSI PDU includes a SCSI command, an IP address of the initiator from which it was received, and an indication of a target storage device to which the iSCSI PDU is addressed. The facility maps IP address of the initiator from which the iSCSI PDU was received to a globally unique IP address and sends the iSCSI PDU to the indicated target storage device. When a response to the iSCSI PDU is received, the facility maps the globally unique IP address to the IP address of the initiator from which the iSCSI PDU was received and forwards the response to the initiator. In some embodiments, the facility is transparent to the iSCSI initiators.

Claims

1. An apparatus comprising:

a receive unit to receive IP packets from a plurality of hosts directed to an IP-based SAN, wherein each received IP packet includes an encapsulated SCSI command, a local IP address corresponding to a host from which the IP packet was received, and a storage device identifier of a storage device within the IP-based SAN to which the IP packet is addressed; and

an impersonation unit to, for each received IP packet;

map the local IP address of the received IP packet to a single globally unique IP address of the apparatus;

modify the received IP packet by removing the local IP address; and

send the modified IP packet to the storage device to which the IP packet is addressed;

wherein each modified IP packet sent by the apparatus to the IP-based SAN includes the storage device identifier and includes the single globally unique IP address that identifies the apparatus as the host from which the IP packet is sent.

2. The apparatus of claim 1 further comprising a response unit to receive a response from the storage device to which the IP packet was addressed, wherein the response includes an indication of the storage device and the single globally unique IP address to which the response is addressed;

and

wherein the impersonation unit maps the single globally unique IP address to the local IP address and sends the response to the host corresponding to the local IP address; and

wherein the apparatus is transparent to the host.

3. The apparatus of claim 2 wherein the impersonation unit performs network address translation (NAT) to map between the local IP address and the single globally unique IP address.

4. The apparatus of claim 3 further comprising a NAT table, wherein the NAT table includes a plurality of entries, each entry corresponding to one of the plurality of hosts, each entry including a local IP address of the corresponding host, a TCP port number of the corresponding host, and an assigned TCP port number of the corresponding host.

5. The apparatus of claim 1 further comprising a report generator to generate a human-readable report describing the received IP packets.

6. The apparatus of claim 5 wherein the report includes a first indication of the host from which each IP packet was received and a second indication of the storage device to which each IP packet was addressed.

7. The apparatus of claim 5 wherein the report is generated periodically and describes a periodic interval for which it is generated.

8. The apparatus of claim 5 wherein the report is generated in response to an event.

9. The apparatus of claim 1 wherein the apparatus is one of the plurality of hosts.

10. The apparatus of claim 9 further comprising an iSCSI daemon.

11. The apparatus of claim 1 wherein the apparatus does not include an iSCSI driver.

12. The apparatus of claim 1 further comprising an iSCSI initiator to generate a SCSI command directed to a storage device of the IP-based SAN and encapsulate the generated SCSI command in one or more IP packets, wherein the one or more IP packets include:

the SCSI command, an apparatus identity, and an indication of the storage device to which the SCSI command is addressed; and

wherein the impersonation unit sends the one or more IP packets to the indicated storage device without mapping the apparatus identity to the single globally unique IP address.

13. The apparatus of claim 12 wherein the apparatus identity is the same as the single globally unique IP address.

14. The apparatus of claim 12 wherein the iSCSI initiator is implemented in an iSCSI driver that includes a USE_PROXY option, and wherein the USE_PROXY option is disabled.

15. A method comprising:

receiving, at a proxy device, messages from a plurality of host devices directed to at least one target device within an IP-based storage area network, wherein each received message includes a SCSI command, a host identity corresponding to a host device from which the message was received, and a target identifier of a target device within the IP-based storage network to which the message is directed; and

for each received message;

mapping the host identity of each received message to a single globally unique IP address corresponding to the proxy device;

removing the host identity from the received message; and

sending the message from the proxy device to the target device;

wherein messages sent by the proxy device to the IP-based storage area network include the target identifier and include the single globally unique IP address that identifies the proxy device as the host device from which the message is sent.

16. The method of claim 15 further comprising, in response to sending the message to the target device,

receiving at the proxy device a response from the target device, wherein the response includes a target identity corresponding to the target device and the single globally unique IP address to which the response is directed;

mapping the single globally unique IP address to the host identity; and

sending the response from the proxy device to the host device corresponding to the host identity.

17. The method of claim 15 wherein the proxy device is one of the plurality of host devices.

18. The method of claim 17 wherein the proxy device includes an iSCSI daemon.

19. The method of claim 15 wherein the proxy device does not include an iSCSI driver.

20. The method of claim 15 wherein the method is performed by the proxy device.

21. The method of claim 20 further comprising:

generating a SCSI command directed to the at least one target device within the IP-based storage area network;

generating a message that includes the SCSI command, a proxy identity, and an indication of the at least one target device to which the SCSI command is directed; and

sending the generated message to the at least one target device without mapping the proxy identity to the single globally unique IP address.

22. The method of claim 15 wherein each received message is an iSCSI datagram.

23. The method of claim 15 further comprising maintaining a log of the received messages;

and

in response to receiving a reporting request, generating a human-readable report based on the maintained log.

24. The method of claim 23 wherein the log includes, for each received message, a first indication of the host device from which the message was received and a second indication of the target device to which the message was directed.