Multi-chassis, multi-path storage solutions in storage area networks

• US 20060047850A1
• Filed: 08/31/2004
• Published: 03/02/2006
• Est. Priority Date: 08/31/2004
• Status: Abandoned Application

• Current Assignee: EMC Corporation (Dell Technologies Inc.)
• Original Assignee: EMC Corporation (Dell Technologies Inc.)
• Inventors: Zhang, Chao, Gandhi, Shreyas P., Verma, Ambrish, Singh Bhasin, Harinder Pal
• Application Number:
  US10/931,504
• Publication Number:
  US 20060047850A1
• Time in Patent Office: Days
• US Class Current: 709/238
• 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 69/40 for recovering from a failure of a protocol instance or entity, e.g. service redundancy protocols, protocol state redundancy or protocol service redirection management of faults, events, alarms or notifications in data switching networks H04L41/06

Abstract

Systems and methods in accordance with various disclosed embodiments are provided for multi-chassis, multi-pathing solutions in storage area networks. A physical target connected to a first storage switch can be virtualized as a member of a virtual logical unit at a second storage switch to which the physical target is not connected. An inter-chassis link can be provided between the storage switches. If the first storage switch becomes inaccessible, the physical target can be accessed via the second storage switch. A virtual logical unit can also be provisioned at the first switch with a member corresponding to the same physical target. The virtual logical units provisioned at each storage switch can be assigned the same identifier to create a clustered virtual logical unit apparent to host devices. Multiple paths to the same logical unit are thus provided to host devices via either switch.

Claims

1. A storage switch for accessing virtual targets, comprising:

at least one virtual logical unit configuration including at least one member associated with at least one physical target coupled to a different storage switch; and

a communications link to said different storage switch.

2. The storage switch of claim 1, wherein:

said virtual logical unit configuration includes a virtual target descriptor identifying flow information to access said at least one physical target.

3. The storage switch of claim 2, wherein:

said communications link includes a first processing unit in communication with said different storage switch; and

said flow information identifies said first processing unit.

4. The storage switch of claim 2, wherein:

said flow information is a Flow ID.

5. The storage switch of claim 1, wherein:

said at least one physical target is at least one first physical target;

said at least one virtual logical unit configuration further includes a second member associated with at least one second physical target coupled to the storage switch.

6. The storage switch of claim 4, wherein:

said at least one virtual logical unit configuration is a mirrored virtual logical unit configuration; and

said at least one member and said second member are mirrored members of said mirrored virtual logical unit configuration.

7. The storage switch of claim 4, wherein:

said communications link includes a first port;

the storage switch further comprises a second port in communication with said at least one second physical target coupled to the storage switch; and

requests for said virtual logical unit configuration are routed to said first port and said second port.

8. The storage switch of claim 7, wherein:

said virtual logical unit configuration includes a virtual target descriptor identifying a processing unit for said first port and a processing unit for said second port.

9. The storage switch of claim 1, wherein:

said at least one virtual logical unit configuration comprises a portion of a clustered virtual logical unit configuration.

10. The storage switch of claim 1, wherein:

said communications link to said different storage switch includes a port coupled to a second storage switch, said second storage switch is coupled to said different storage switch.

11. The storage switch of claim 1, wherein:

said communications link communicates with said different storage switch over an inter-chassis link.

12. The storage switch of claim 1, wherein:

said communications link communicates with said different storage switch over a fibre-channel connection.

13. The storage switch of claim 1, wherein:

said communications link communicates with said different storage switch over an ethernet connection.

14. The storage switch of claim 1, wherein:

said communications link communicates with said different storage switch over an internet protocol connection.

15. The storage switch of claim 1, further comprising:

a memory storing said at least one virtual logical unit configuration.

16. The storage switch of claim 1, wherein:

said at least one member is at least one remote member.

17. A method of provisioning virtual targets, comprising:

provisioning at a first device a member corresponding to at least one physical target coupled to a second device; and

provisioning at said first device a virtual logical unit configuration including said first member.

18. The method of claim 17, wherein:

said member is a first member;

said at least one physical target coupled to said second device is at least one first physical target;

said method further comprises provisioning at said first device a second member corresponding to at least one second physical target coupled to the first device; and

said step of provisioning at said first device a virtual logical unit configuration includes provisioning said virtual logical unit configuration to include said second member.

19. The method of claim 18, wherein:

said virtual logical unit configuration is a mirrored virtual logical unit configuration; and

said first member and said second member are mirrored members of said mirrored virtual logical unit configuration.

20. The method of claim 18, wherein said step of provisioning said virtual logical unit configuration includes

provisioning a virtual target descriptor for said configuration, said virtual target descriptor identifying a location of said at least one second physical target at said first device and a location of a first processing unit at said first device in communication with said second device.

21. The method of claim 17, wherein:

said virtual logical unit configuration includes a virtual target descriptor identifying a location of a first processing unit at said first device in communication with said second device.

22. One or more processor readable storage devices having processor readable code embodied on said one or more processor readable storage devices, said processor readable code for programming one or more processors to perform a method comprising:

provisioning at a first device a member corresponding to at least one physical target coupled to a second device; and

provisioning at said first device a virtual logical unit configuration including said first member.

23. One or more processor readable storage devices according to claim 22, wherein:

said member is a first member;

said at least one physical target coupled to said second device is at least one first physical target;

said method further comprises provisioning at said first device a second member corresponding to at least one second physical target coupled to the first device; and

said step of provisioning at said first device a virtual logical unit configuration includes provisioning said virtual logical unit configuration to include said second member.

24. One or more processor readable storage devices according to claim 23, wherein:

said virtual logical unit configuration is a mirrored virtual logical unit configuration; and

said first member and said second member are mirrored members of said mirrored virtual logical unit configuration.

25. One or more processor readable storage devices according to claim 23, wherein said step of provisioning said virtual logical unit configuration includes:

provisioning a virtual target descriptor for said configuration, said virtual target descriptor identifying a location of a first processing unit at said first device in communication with said second device.

26. One or more processor readable storage devices according to claim 22, wherein:

said virtual logical unit configuration includes a virtual target descriptor identifying a location of a first processing unit at said first device in communication with said second device.

27. A system for accessing virtual targets, comprising:

a clustered virtual logical unit including at least one first virtual logical unit provisioned at a first storage switch and at least one second virtual logical unit provisioned at a second storage switch, said first virtual logical unit and said second virtual logical unit having a same logical unit identifier.

28. The system of claim 27, wherein:

said first virtual logical unit includes a first member associated with at least a first physical target coupled to said first storage switch; and

said second virtual logical unit includes a first remote member associated with said at least a first physical target coupled to said first storage switch.

29. The system of claim 28, wherein:

said first virtual logical unit includes a second remote member associated with at least a second physical target coupled to said second storage switch;

said second virtual logical unit includes a second member associated with said at least a second physical target coupled to said second storage switch.

30. The system of claim 29, wherein:

said first virtual logical unit is a mirrored virtual logical unit;

said first member and said second remote member are mirrored members of said first virtual logical unit;

said second virtual logical unit is a mirrored virtual logical unit; and

said first remote member and said second member are mirrored members of said second virtual logical unit.

31. The system of claim 27, further comprising:

a storage services manager at said second switch associated with said clustered virtual logical unit.

32. The system of claim 31, wherein:

said first storage switch provides a control message to said storage services manager when said first storage switch receives a request for said clustered virtual logical unit.

33. The system of claim 32, wherein:

said storage services manager manages processing of said request byu forwarding a response message to said first storage switch to begin processing said request.

34. The system of claim 32, wherein:

said first storage switch queues said request when sending said control message.

35. The system of claim 27, wherein:

said logical unit identifier is a virtual logical unit identification.

36. The system of claim 27, further comprising:

a communications link between said first storage switch and said second storage switch;

wherein requests for said at least one first virtual logical unit are provided to said second storage switch over said communications link;

wherein requests for said at least one second virtual logical unit are provided to said first storage switch over said communications link.

37. The system of claim 27, wherein:

said clustered virtual logical unit is a mirrored clustered virtual logical unit;

said at least one first virtual logical unit is a mirrored virtual logical unit;

said at least one second virtual logical unit is a mirrored virtual logical unit.

38. A method of accessing virtual targets, comprising:

provisioning a first virtual logical unit at a first storage switch;

associating said first virtual logical unit with a logical unit identifier;

provisioning a second virtual logical unit at a second storage switch; and

associating said second virtual logical unit with said logical unit identifier.

39. The method of claim 38, wherein:

said method further comprises;

provisioning at said first storage switch a first member corresponding to at least one physical target coupled to said first storage switch, and

provisioning at said second storage switch a first remote member corresponding to said at least one physical target;

said step of provisioning a first virtual logical unit includes provisioning said first member as a member of said first virtual logical unit; and

said step of provisioning a second virtual logical unit includes provisioning said first remote member as a member of said second virtual logical unit.

40. The method of claim 38, wherein:

said at least one physical target is at least one first physical target;

said method further comprises;

provisioning at said first storage switch a second remote member corresponding to at least one second physical target coupled to said second storage switch,

provisioning at said second storage switch a second member corresponding to said at least one second physical target;

said step of provisioning a first virtual logical unit includes provisioning said second remote member as a member of said first virtual logical unit; and

said step of provisioning a second virtual logical unit includes provisioning said second member as a member of said second virtual logical unit.

41. The method of claim 40, wherein:

said step of provisioning a first virtual logical unit includes provisioning said first virtual logical unit as a mirrored virtual logical unit having said first member and said second remote member as mirrored members;

said step of provisioning a second virtual logical unit includes provisioning said second virtual logical mirrored virtual logical unit having said first remote member and said second member as mirrored members.

42. The method of claim 41, wherein:

said steps of associating said first virtual logical unit with a logical unit identifier and associating said second virtual logical unit with said logical unit identifier include creating a mirrored clustered virtual logical unit.

43. The method of claim 38, wherein:

said steps of associating said first virtual logical unit with a logical unit identifier and associating said second virtual logical unit with said logical unit identifier include creating a clustered virtual logical unit.

44. One or more processor readable storage devices having processor readable code embodied on said one or more processor readable storage devices, said processor readable code for programming one or more processors to perform a method comprising:

provisioning a first virtual logical unit at a first storage switch;

associating said first virtual logical unit with a logical unit identifier;

provisioning a second virtual logical unit at a second storage switch; and

associating said second virtual logical unit with said logical unit identifier.

45. One or more processor readable storage devices according to claim 44, wherein:

said method further comprises;

provisioning at said first storage switch a first member corresponding to at least one physical target coupled to said first storage switch, and

provisioning at said second storage switch a first remote member corresponding to said at least one physical target;

said step of provisioning a first virtual logical unit includes provisioning said first member as a member of said first virtual logical unit; and

said step of provisioning a second virtual logical unit includes provisioning said first remote member as a member of said second virtual logical unit.

46. One or more processor readable storage devices according to claim 45, wherein:

said at least one physical target is at least one first physical target;

said method further comprises;

provisioning at said first storage switch a second remote member corresponding to at least one second physical target coupled to said second storage switch,

provisioning at said second storage switch a second member corresponding to said at least one second physical target;

said step of provisioning a first virtual logical unit includes provisioning said second remote member as a member of said first virtual logical unit; and

said step of provisioning a second virtual logical unit includes provisioning said second member as a member of said second virtual logical unit.

47. One or more processor readable storage devices according to claim 46, wherein:

said step of provisioning a first virtual logical unit includes provisioning said first virtual logical unit as a mirrored virtual logical unit having said first member and said second remote member as mirrored members;

said step of provisioning a second virtual logical unit includes provisioning said second virtual logical mirrored virtual logical unit having said first remote member and said second member as mirrored members.

48. One or more processor readable storage devices according to claim 47, wherein:

said steps of associating said first virtual logical unit with a logical unit identifier and associating said second virtual logical unit with said logical unit identifier include creating a mirrored clustered virtual logical unit.

49. One or more processor readable storage devices according to claim 44, wherein:

said steps of associating said first virtual logical unit with a logical unit identifier and associating said second virtual logical unit with said logical unit identifier include creating a clustered virtual logical unit.

50. A method of provisioning virtual targets, comprising:

provisioning at a first storage switch a first member corresponding to at least one physical target coupled to said first storage switch;

provisioning at a second storage switch a first remote member corresponding to said at least one physical target;

provisioning at said first storage switch a first virtual logic unit including said first member, said provisioning including associating a first logical unit identifier with said first virtual logic unit; and

provisioning at said second switch a second virtual logical unit including said first remote member, said provisioning including associating said first logical unit identifier with said second virtual logic unit.

51. The method of claim 50, wherein:

said steps of provisioning at said first storage switch a first virtual logical unit and provisioning at said second storage switch a second virtual logical unit include creating a clustered virtual logical unit comprised of said first virtual logical unit and said second virtual logical unit.

52. The method of claim 51, wherein:

said at least one physical target is at least one first physical targets;

said method further comprising;

provisioning at said first storage switch a second remote member corresponding to at least one second physical target coupled to said second storage switch;

provisioning at said second storage switch a second member corresponding to said at least one second physical target;

said step of provisioning at said first storage switch a first virtual logical unit includes provisioning said second remote member as a member of said first virtual logical unit; and

said step of provisioning at said second storage switch a second virtual logical unit includes provisioning said second member as a member of said second virtual logical unit.

53. The method of claim 52, wherein:

said step of provisioning at said first storage switch a first virtual logical unit includes provisioning said first virtual logical unit as a mirrored virtual logical unit having said first member and said second remote member as mirrored members; and

said step of provisioning at said second storage switch a second virtual logical unit includes provisioning said second virtual logical unit as a mirrored virtual logical unit having said first remote member and said second member as mirrored members.

54. The method of claim 52, wherein:

said steps of provisioning at said first storage switch a first virtual logical unit and provisioning at said second storage switch a second virtual logical unit include creating a mirrored clustered virtual logical unit comprised of said first virtual logical unit and said second virtual logical unit.