Storage Router and Method for Providing Virtual Local Storage

• US 20110040949A1
• Filed: 10/22/2010
• Published: 02/17/2011
• Est. Priority Date: 12/31/1997
• Status: Active Grant

• Current Assignee: Crossroads Systems (Texas) Incorporated (Crossroads Systems, Inc.)
• Original Assignee: Crossroads Systems (Texas) Incorporated (Crossroads Systems, Inc.)
• Inventors: Russell, Jeffry T., Hoese, Geoffrey B.
• Granted Patent: US 7,984,224 B2
• Time in Patent Office: Days
• US Class Current: 711/172
• CPC Class Codes: G06F 13/1668 Details of memory controller
• CPC Class Codes: G06F 13/385 for adaptation of a particular data processing system to different peripheral devices
• CPC Class Codes: G06F 13/4022 using switching circuits, e.g. switching matrix, connection or expansion network G06F13/4009 takes precedence
• CPC Class Codes: G06F 13/4059 where the synchronisation uses buffers, e.g. for speed matching between buses
• CPC Class Codes: G06F 3/0601 Interfaces specially adapted for storage systems
• CPC Class Codes: G06F 3/0605 by facilitating the interaction with a user or administrator
• 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 3/0661 Format or protocol conversion arrangements
• CPC Class Codes: G06F 3/0664 at device level, e.g. emulation of a storage device or system
• CPC Class Codes: G06F 3/067 Distributed or networked storage systems, e.g. storage area networks [SAN], network attached storage [NAS]
• CPC Class Codes: G06F 3/0673 Single storage device
• 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 61/106 across networks, e.g. mapping telephone numbers to data network 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]
• CPC Class Codes: H04L 67/568 Storing data temporarily at an intermediate stage, e.g. caching

Abstract

A storage router and method for providing virtual local storage on remote storage devices to devices are provided. Devices are connected to a first transport medium, and a plurality of storage devices are connected to a second transport medium. In one embodiment, the storage router maintains a map to allocate storage space of the discovered storage devices to devices connected to the first transport medium by associating representations of the devices connected to the first transport medium with representations of the storage space and controls access from the devices connected to the first transport medium to the discovered storage devices in accordance with the map and using native low level block protocols.

Claims

1. A storage router for providing virtual local storage on remote storage devices, comprising:

a first controller operable to interface with a first transport medium, wherein the first medium is a serial transport media; and

a second controller to interface with a second transport medium;

a processing device in communication with to the first controller and second controller, wherein the processing device is configured to;

discover the remote storage devices as presented on the second transport medium;

maintain a map to allocate storage space of the discovered storage devices to devices connected to the first transport medium by associating representations of the devices connected to the first transport medium with representations of the storage space, wherein each representation of a device connected to the first transport medium is associated with one or more representations of storage space;

present the allocated storage space as virtual local storage to the associated devices connected to the first transport medium;

control access from the devices connected to the first transport medium to the discovered storage devices in accordance with the map and using native low level block protocols.

2. The storage router of claim 1, wherein the map associates a representation of storage space with multiple devices connected to the first transport medium.

3. The storage router of claim 1, wherein the storage space comprises storage space on multiple remote storage devices.

4. The storage router of claim 1, wherein, for storage space allocated to a device connected to the first transport medium, the storage router presents to that device a LUN discovered on the second transport medium for that storage space.

5. The storage router of claim 1, wherein, for storage space allocated to a device connected to the first transport medium, the storage router presents to that device a different LUN than the LUN discovered on the second transport medium for that storage space.

6. The storage router of claim 1, wherein the map resides at the storage router and is maintained at the storage router.

7. The storage router of claim 1, wherein the native low level block protocol is received at the storage router via the first transport medium and the processing device uses the received native low level block protocol to allow the devices connected to the first transport medium access to storage space specifically allocated to them in the map.

8. The storage router of claim 1, wherein the storage router is configured to receive commands according to a first low level block protocol from the device connected to the first transport medium and forward commands according to a second low level block protocol on the second transport medium.

9. The storage router of claim 1, wherein the map comprises one or more tables.

10. The storage router of claim 1, wherein the virtual local storage is provided to the devices connected to the first transport medium in a manner that is transparent to the devices and wherein storage space allocated to the devices connected to the first transport medium appears to the devices as local storage.

11. The storage router of claim 1, wherein the storage router provides centralized control of what the devices connected to the first transport medium see as local storage.

12. The storage router of claim 1, wherein the representations of storage space comprise logical unit numbers that represent a subset of storage on the remote storage devices.

13. The storage router of claim 12, wherein the storage router is operable to route requests to the same logical unit number from different devices connected to the first transport medium to different subsets of storage space on the remote storage devices.

14. The storage router of claim 1, wherein the representations of devices connected to the first transport medium are unique identifiers.

15. The storage router of claim 14, wherein the unique identifiers are world wide names.

16. The storage router of claim 1, wherein the storage router is configured to allow modification of the map in a manner transparent to and without involvement of the devices connected to the first transport medium.

17. The storage router of claim 1, wherein the processing device is a microprocessor.

18. The storage router of claim 1, wherein the processing device is a microprocessor and associated logic to implement a stand-alone processing system.

19. The storage router of claim 1, wherein the first transport medium is a fibre channel transport medium and further comprising a second transport medium connected to the remote storage devices that is a fibre channel transport medium.

20. The storage router of claim 1, wherein the storage router is operable to communicate a device connected to the first transport medium via Ethernet.

21. A method for providing virtual local storage on remote storage devices comprising:

connecting a storage router to a first transport medium and a second transport medium;

discovering the remote storage devices as presented on the second transport medium, wherein the storage router performs the discovering;

maintaining a map at the storage router to allocate storage space on the discovered storage devices to devices connected to the first transport medium by associating representations of the devices connected to the first transport medium with representations of storage space, wherein each representation of a device connected to the first transport medium is associated with one or more representations of storage space; and

controlling access from the devices connected to the first transport medium to the storage space in accordance with the map and using native low level block protocol.

22. The method of claim 21, wherein the map associates a representation of storage space on the remote storage devices with multiple devices connected to the first transport medium.

23. The method of claim 21, wherein the storage space on the remote storage devices comprises storage space on multiple remote storage devices.

24. The method of claim 21, wherein the map associates a representation of a device connected to the first transport medium with a representation of an entire storage space of at least one remote storage device.

25. The method of claim 21, wherein the map resides at the storage router and is maintained at the storage router.

26. The method of claim 21, further comprising:

receiving the native low level block protocol at the storage router via the first transport medium;

using the received native low level block protocol at the storage router to allow the devices connected to the first transport medium access to storage space specifically allocated to them in the map.

27. The method of claim 21, further comprising receiving commands at the storage router according to a first low level block protocol from the device connected to the first transport medium and forwarding commands according to a second low level block protocol on the second transport medium.

28. The method of claim 21, wherein the map comprises one or more tables.

29. The method of claim 21, wherein the virtual local storage is provided to the devices connected to the first transport medium in a manner that is transparent to the devices and wherein the storage space allocated to the devices connected to the first transport medium appears to the devices as local storage.

30. The method of claim 21, wherein the storage router provides centralized control of what the devices connected to the first transport medium see as local storage.

31. The method of claim 21, wherein the representations of storage space comprise logical unit numbers that represent a subset of storage on the remote storage devices.

32. The method of claim 31, wherein the storage router is operable to route requests to the same logical unit number from different devices connected to the first transport medium to different subsets of storage space.

33. The method of claim 21, wherein the representations of devices connected to the first transport medium are unique identifiers.

34. The method of claim 33, wherein the unique identifiers are world wide names.

35. The method of claim 21, wherein the storage router is configured to allow modification of the map in a manner transparent to and without involvement of the devices connected to the first transport medium.

36. The method of claim 21 further comprising, for storage space allocated to a device connected to the first transport medium, presenting to that device a LUN discovered on the second transport medium for that storage space.

37. The method of claim 21 further comprising, for storage space allocated to a device connected to the first transport medium, presenting to that device a different LUN than the LUN discovered on the second transport medium for that storage space.

38. The method of claim 21, further comprising between the storage router and at least at least one device connected to the first transport using Ethernet.