Storage area network interconnect server

• US 7,526,527 B1
• Filed: 03/31/2003
• Issued: 04/28/2009
• Est. Priority Date: 03/31/2003
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Woodruff, Roger
• Primary Examiner(s): Lin; Kenny S
• Assistant Examiner(s): WIDHALM, ANGELA M
• Application Number:
  US10/403,365
• Time in Patent Office: 2,220 Days
• Field of Search: 709217-226
• US Class Current: 709/212
• CPC Class Codes: H04L 2101/631 Small computer system interface [SCSI] addresses
• CPC Class Codes: H04L 2101/645 Fibre channel identifiers
• CPC Class Codes: H04L 61/2596 Translation of addresses of the same type other than IP, e.g. translation from MAC to MAC 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

Systems and methods for interconnecting a SAN with hosts on a remote network are disclosed. The systems and methods receive a set of device identifiers for a set of physical storage devices on the SAN. The device identifiers are mapped to a set of virtual device identifiers. Virtual devices having the virtual device identifiers are created on the remote network. The virtual devices correspond with the physical devices. Commands and responses are mapped and communicated between the virtual devices and the corresponding physical devices.

Claims

1. A method for providing access to a storage area network, the method comprising:

accessing a storage router connected to a set of physical storage devices on the storage area network, the storage router including a plurality of SCSI routers assigned a plurality of IP addresses;

issuing a discovery request to the storage router to determine the presence of the set of physical devices on the storage area network;

receiving a set of device identifiers for the set of physical storage devices on an iSCSI interconnect router;

mapping the set of identifiers to a set of virtual device identifiers;

presenting to a host on a second network a set of virtual storage devices corresponding to the set of physical storage devices and identified by the set of virtual device identifiers;

waiting a predetermined period of time to determine if changes in the set of physical devices exist;

updating the set of virtual storage devices in accordance with the changes.

2. The method of claim 1, wherein the predetermined time is sixty seconds.

3. The method of claim 1, wherein determining if changes exist includes determining changes in iSCSI targets on the physical devices.

4. A method for interconnecting a storage device on a storage area network to a host on a remote network, the method comprising:

accessing a storage router connected to a set of physical storage devices on the storage area network, the storage router including a plurality of SCSI routers assigned a plurality of IP addresses;

receiving from the host a request to open a target on a virtual device presented on the remote network, said virtual device corresponding to a physical device on the storage area network and coupled to the storage router;

receiving a command from the host for the target on the virtual device;

opening an iSCSI connection to a target on the physical device coupled to the storage router using one of the plurality of SCSI routers;

if the connection succeeds, then issuing the command to the target on the physical device, otherwise waiting a predetermined time and repeating the attempt to open an iSCSI connection to the target on the physical device.

5. A method for maintaining a connection between a physical storage device on a storage area network and a virtual storage device presented on a remote network, the method comprising:

accessing a storage router connected to a set of physical storage devices on the storage area network, the storage router including a plurality of SCSI routers assigned a plurality of IP addresses, wherein at least one of the plurality of SCSI routers manages one or more iSCSI connections to one or more targets on the physical storage device;

mapping a virtual storage device to a physical storage device on a storage area network connected to the storage router through one of the plurality of SCSI routers;

determining if a command is currently being processed by the physical storage device;

if no command is currently being processed, then;

sending a no-op command to the physical storage device,

waiting up to a predetermined time to determine if a response is received from the physical storage device, and

if no response is received, then determining if a maximum waiting time has elapsed and if so closing the connection.

6. The method of claim 5, wherein the predetermined time is sixty seconds.

7. The method of claim 5, wherein the maximum waiting time is 180 seconds.

8. The method of claim 5, wherein the command is a SCSI command.

9. A tangible computer-readable storage medium having stored thereon computer executable instructions for performing a method for providing access to a storage area network, the method comprising:

accessing a storage router connected to a set of physical storage devices on the storage area network, the storage router including a plurality of SCSI routers assigned a plurality of IP addresses;

issuing a discovery request to the storage router to determine the presence of the set of physical devices on the storage area network;

receiving a set of device identifiers for the set of physical storage devices on an iSCSI interconnect router;

mapping the set of identifiers to a set of virtual device identifiers;

presenting to a host on a second network a set of virtual storage devices corresponding to the set of physical storage devices and identified by the set of virtual device identifiers;

waiting a predetermined period of time to determine if changes in the set of physical devices exist;

updating the set of virtual storage devices in accordance with the changes.

10. The tangible computer-readable storage medium of claim 9, wherein the predetermined time is sixty seconds.

11. The tangible computer-readable storage medium of claim 9, wherein determining if changes exist includes determining changes in iSCSI targets on the physical devices.

12. A tangible computer-readable storage medium having stored thereon computer executable instructions for performing a method for interconnecting a storage device on a storage area network to a host on a remote network, the method comprising:

accessing a storage router connected to a set of physical storage devices on the storage area network, the storage router including a plurality of SCSI routers assigned a plurality of IP addresses;

receiving from the host a request to open a target on a virtual device presented on the remote network, said virtual device corresponding to a physical device on the storage area network and coupled to the storage router;

receiving a command from the host for the target on the virtual device;

opening an iSCSI connection to a target on the physical device coupled to the storage router using one of the plurality of SCSI routers;

if the connection succeeds, then issuing the command to the target on the physical device, otherwise waiting a predetermined time and repeating the attempt to open an iSCSI connection to the target on the physical device.

13. A tangible computer-readable storage medium having stored thereon computer executable instructions for performing a method for maintaining a connection between a physical storage device on a storage area network and a virtual storage device presented on a remote network, the method comprising:

accessing a storage router connected to a set of physical storage devices on the storage area network, the storage router including a plurality of SCSI routers assigned a plurality of IP addresses, wherein at least one of the plurality of SCSI routers manages one or more iSCSI connections to one or more targets on the physical storage device;

mapping a virtual storage device to a physical storage device on a storage area network connected to the storage router through one of the plurality of SCSI routers;

determining if a command is currently being processed by the physical storage device;

if no command is currently being processed, then;

sending a no-op command to the physical storage device,

waiting up to a predetermined time to determine if a response is received from the physical storage device, and

if no response is received, then determining if a maximum waiting time has elapsed and if so closing the connection.

14. The tangible computer-readable storage medium of claim 13, wherein the predetermined time is sixty seconds.

15. The tangible computer-readable storage medium of claim 13, wherein the maximum waiting time is 180 seconds.

16. The tangible computer-readable storage medium of claim 13, wherein the command is a SCSI command.

17. A computerized system comprising:

means for accessing a storage router connected to a set of physical storage devices on the storage area network, the storage router including a plurality of SCSI routers assigned a plurality of IP addresses;

means for issuing a discovery request to the storage router to determine the presence of the set of physical devices on the storage area network;

means for receiving a set of device identifiers for the set of physical storage devices on an iSCSI interconnect router;

means for mapping the set of identifiers to a set of virtual device identifiers;

means for presenting to a host on a second network a set of virtual storage devices corresponding to the set of physical storage devices and identified by the set of virtual device identifiers;

waiting a predetermined period of time to determine if changes in the set of physical devices exist;

means for updating the set of virtual storage devices in accordance with the changes.