DISPATCHING OF SERVICE REQUESTS IN REDUNDANT STORAGE VIRTUALIZATION SUBSYSTEMS

• US 20050240805A1
• Filed: 03/29/2005
• Published: 10/27/2005
• Est. Priority Date: 03/30/2004
• Status: Active Grant

• Current Assignee: Infortrend Technology Incorporated (Infortrend Corporation)
• Original Assignee: Infortrend Technology Incorporated (Infortrend Corporation)
• Inventors: Schnapp, Michael Gordon, Chan, Chih-Chung
• Granted Patent: US 9,015,391 B2
• Time in Patent Office: Days
• US Class Current: 714/6
• CPC Class Codes: G06F 11/2089 Redundant storage control functionality
• CPC Class Codes: G06F 3/0611 in relation to response time
• CPC Class Codes: G06F 3/0619 in relation to data integrity, e.g. data losses, bit errors
• CPC Class Codes: G06F 3/0635 by changing the path, e.g. traffic rerouting, path reconfiguration
• CPC Class Codes: G06F 3/0665 at area level, e.g. provisioning of virtual or logical volumes
• CPC Class Codes: G06F 3/0683 Plurality of storage devices
• CPC Class Codes: G06F 3/0689 Disk arrays, e.g. RAID, JBOD

Abstract

A method for dispatching of service requests in a redundant storage virtualization subsystem including a plurality of storage virtualization controllers is disclosed. The method comprises the steps of the host entity issuing a first service request to a first one of the SVCs; the first SVC handling the first service request, acquiring a first result of servicing the first service request, and returning the first result to the host entity the result; and, the host entity issuing a second service request to a second one of the SVCs; and, the second SVC handling the second service request, acquiring a second result of servicing the second service request, and returning the second result to the host entity the result. A storage virtualization subsystem implementing the method, a computer system comprising such storage virtualization subsystem, and a storage media having machine-executable codes stored therein for performing the method are also disclosed.

Claims

1. A method for dispatching of service requests in a redundant storage virtualization subsystem (SVS) including a plurality of storage virtualization controllers (SVCs), comprising the steps of:

said host entity issuing a first service request to a first one of said SVCs;

said first SVC handling said first service request, acquiring a first result of servicing the first service request, and returning said first result to the host entity the result; and

,

said host entity issuing a second service request to a second one of said SVCs; and

said second SVC handling said second service request, acquiring a second result of servicing the second service request, and returning said second result to the host entity the result.

2. The method defined in claim 1, wherein said second service request is issued after said first result is returned to the host entity.

3. The method defined in claim 1, wherein said second service request is issued before said first result is returned to the host entity.

4. A method for dispatching of service requests in a redundant storage virtualization subsystem (SVS) including a plurality of storage virtualization controllers (SVCs), comprising the steps of:

selecting at least one of the SVCs;

enabling a port on the at least one selected SVC for dispatching of service requests;

issuing at least one service request to said at least one selected SVC;

said at least one service request being handled by said at least one selected SVC;

acquiring a result of servicing the at least one service request by said at least one selected SVC; and

,

returning to the host entity the result by said at least one selected SVC.

5. The method defined in claim 4, wherein said host entity selects only one of said SVCs to issue service requests at a time, and said host entity will not issue service requests to other SVCs until all service requests issued to said one SVC have been serviced to completion.

6. The method defined in claim 5, wherein said selected SVC handles said at least one service request by servicing the service requests.

7. The method defined in claim 4, wherein

said selected SVC handles said at least one service request by forwarding service requests to an owner of service request servicing function;

and,

said selected SVC acquires a result of servicing the at least one service request by receiving a service response from said owner.

8. The method defined in claim 4, wherein said step of said selected SVC handling said at least one service request comprises:

said selected SVC checking if it is an owner of service request servicing function; and

,

if it is not, then said selected SVC conveying a request for ownership transfer to itself, and

said selected SVC servicing the service requests after said selected SVC becomes a owner of service request servicing function.

9. A method for dispatching of service requests in a redundant storage virtualization subsystem (SVS) including a plurality of storage virtualization controllers (SVCs), comprising the steps of:

said host entity selecting a first one of the SVCs to issue service requests;

said first SVC receiving said service requests;

said first SVC completing the servicing of all the received service requests; and

,

said host entity selecting a second one of the SVCs to issue service requests.

10. A method for dispatching of service requests in a redundant storage virtualization subsystem (SVS) including a plurality of storage virtualization controllers (SVCs), comprising the steps of:

a first one of the SVCs receiving a service request from the host entity and forwarding said received service request to a second one of the SVCs;

said second SVC dispatching the service request for servicing;

on completion of request servicing, said second SVC conveying response data and status information to said first SVC; and

,

said first SVC forwarding said response data and status information to the host entity.

11. The method defined in claim 10, wherein when said second SVC is in charge of the dispatching of the service requests, any information associated with said service request conveyed between said host entity and said second SVC will be first conveyed to said first SVC and then forwarded by said first SVC to a destination device.

12. A method for dispatching of service requests in a redundant storage virtualization subsystem (SVS) including a plurality of storage virtualization controllers (SVCs), comprising the steps of:

a first one of the SVCs receiving a service request from the host entity;

determining whether or not said first SVC is a service request servicing function owner;

if said first SVC is the service request servicing function owner, servicing the service requests directly, otherwise issuing a request to a service request servicing function ownership arbiter for an ownership transfer to itself;

said ownership arbiter issuing a request to the servicing function owner to relinquish ownership;

said servicing function owner preparing to relinquish ownership first and then issuing an acknowledgement to said ownership arbiter acknowledging the relinquishing of ownership;

said ownership arbiter issuing an acknowledgement to a said SVC to which ownership is to be transferred and the said SVC becoming a new servicing function owner;

said new servicing function owner starting to service pending service requests; and

,

on completion of request servicing, said new servicing function owner conveying response data and status information to the host entity.

13. The method defined in claim 12, further comprising the step of, after determining said first SVC is not a service request servicing function owner, said first SVC queuing said service requests received by it.

14. The method defined in claim 12, further comprising the steps of, before the step of said first SVC issuing a request for ownership transfer to itself, said first SVC checking if there is any service request that were queued and, if there is, said first SVC not issuing said request for ownership transfer to itself.

15. The method defined in claim 12, wherein the step of preparing to relinquish ownership comprises:

finishing the servicing of any requests currently being serviced; and

, queuing any new service requests that may be received during the process.

16. The method defined in claim 15, further comprising the step of issuing an indication to said ownership arbiter so that ownership of service request servicing function will be restored to it later on.

17. The method defined in claim 12, wherein the step of preparing to relinquish ownership comprises the step of finishing all service requests received by said servicing function owner.

18. The method defined in claim 12, further comprising the step of said ownership arbiter deciding to whom ownership should be transferred.

19. The method defined in claim 12, further comprising the step of said ownership arbiter deciding when a transfer of this function ownership should occur.

20. A method for dispatching of service requests in a redundant storage virtualization subsystem (SVS) including a plurality of storage virtualization controllers (SVCs), comprising the steps of:

a first one of the SVCs receiving a service request from the host entity;

determining whether or not said first SVC is a service request servicing function owner;

if said first SVC is the service request servicing function owner, servicing the service requests directly, otherwise issuing a request to said servicing function owner for an ownership transfer to itself;

said servicing function owner determining an appropriate time to start the process of relinquishing ownership and preparing the relinquishing of ownership;

said servicing function owner issuing an acknowledgement to a said SVC to which ownership is to be transferred and the said SVC becoming a new servicing function owner;

said new servicing function owner starting to servicing pending service requests; and

, on completion of request servicing, said new servicing function owner conveying response data and status information to the host entity.

21. The method defined in claim 20, further comprising the step of said first SVC queuing said service requests received by it, after determining said first SVC is not a service request servicing function owner.

22. The method defined in claim 21, wherein before the step of said first SVC issuing a request for ownership transfer to itself, said first SVC checks if there is any service request that were queued, and if there is, said SVC not issuing said request for ownership transfer to itself.

23. The method defined in claim 20, wherein the step of preparing to relinquish ownership comprises:

finishing the servicing of any requests currently being serviced; and

, queuing any new service requests that may be received during the process.

24. The method defined in claim 23, further comprising the step of issuing an indication to said first SVC so that ownership of service request servicing function will be restored to it later on.

25. The method defined in claim 20, wherein the step of preparing to relinquish ownership comprises finishing all service requests received by said servicing function owner.

26. The method defined in claim 20, further comprising the step of:

said original servicing function owner conveying updated configuration, state and status information to all the other SVCs.

27. The method defined in claim 20, further comprising the step of:

said original servicing function owner deciding to whom ownership should be transferred.

28. The method defined in claim 27, further comprising the step of:

said original servicing function owner forwarding the other ownership transfer requests received by it to said decided SVC, while informing said decided SVC that ownership has been relinquished.

29. The method defined in claim 20, further comprising the step of:

said original servicing function owner informing the other SVCs who is the new owner.

30. The method defined in claim 29, wherein when the other SVCs receive said information of new owner, if it is waiting for an acknowledgement that ownership has been relinquished, then it conveys to the new owner the request for ownership transfer to itself.

31. A storage virtualization computer system comprising:

a host entity for issuing service requests;

a plurality of storage virtualization controllers (SVCs) coupled to said host entity; and

,

a plurality of physical storage devices, each coupled to said SVCs and accessed by said SVCs, for providing storage to said storage virtualization computer system;

wherein said host entity can discover at least two SVCs and convey service request through interconnects to said at least two SVCs, and only one of said at least two SVCs can service the service requests at a time.

32. The computer system defined in claim 31, wherein said at least two SVCs formed into a redundant configuration, and having an inter-controller communications channel between said at least two SVCs over which they can communicate.

33. The computer system defined in claim 31, wherein said host entity selects only one of said SVCs to issue service requests at a time, and said host entity will not issue service requests to other SVCs until all service requests issued to said one SVC have been serviced to completion.

34. The computer system defined in claim 33, wherein said host entity checks if all service requests issued to said one SVC have been serviced to completion before issuing a new service request.

35. The computer system defined in claim 34, wherein if said service requests issued to said one SVC have not been serviced to completion, said host entity selects one of said SVCs to issue said new service request after the service requests have been serviced to completion.

36. The computer system defined in claim 34, wherein if said service requests issued said one SVC have not been serviced to completion, said host entity selects the said one SVC to issue said new service request.

37. The computer system defined in claim 31, wherein said SVCs further comprises

at least one service request forwarder SVC therein for forwarding all service requests received to a primary SVC for servicing;

said primary SVC receiving service requests issued directly by said host entity or forwarded by said forwarder, servicing said requests and

sending the associated response data and status information to the entity that originally issued said request to said primary SVC.

38. The computer system defined in claim 37, wherein if said primary SVC loses the capacity to perform its service request servicing functionality, said forwarder would take over the function of said primary SVC.

39. The computer system defined in claim 31, wherein said SVCs comprises a service request servicing function ownership arbiter SVC therein for maintaining that only one of said SVCs is the owner of service request servicing function at a time.

40. The computer system defined in claim 39, wherein

when said SVC receives a service request from said host entity, said SVC checks if it is a current owner of service request servicing function;

if it is, then the said SVC services the request;

if the said SVC is not the current owner, then the said SVC conveys to said ownership arbiter a request for ownership transfer to itself, and starts to service said service request after receiving an acknowledgement from said ownership arbiter.

41. The computer system defined in claim 40, wherein when said ownership arbiter receives said request from the said ownership requester SVC, said ownership arbiter issues a request to a current service request servicing function owner to relinquish ownership, and then said ownership arbiter receives from said owner an acknowledgement that ownership has been relinquished and informs the said ownership requester SVC.

42. The computer system defined in claim 40, wherein said ownership arbiter is the current owner of service request servicing function.

43. The computer system of claim 41, wherein when said owner receives said request, said owner would be responsible for relinquishing ownership at a convenient time and issues an acknowledgement that ownership has been relinquished to inform the entity that originally issued said request to said owner.

44. A storage virtualization subsystem (SVS) comprising:

a plurality of storage virtualization controllers(SVCs) coupled to a host entity; and

,

a plurality of physical storage devices, each coupled to said SVCs and accessed by said SVCs, for providing storage to said host entity;

wherein said host entity can discover said SVCs and convey service request through the connections to said SVCs, and only one of said SVCs can service the service requests at a time.

45. The subsystem defined in claim 44, wherein said SVCs further comprises:

at least one service request forwarder SVC therein for forwarding all service requests received form said host entity to an owner of service request servicing function;

said owner receiving service requests issued directly by said host entity or forwarded by said forwarder, servicing said requests and sending the associated response data and status information to the entity that originally issued said request to said owner.

46. The subsystem defined in claim 45, wherein if said owner loses the capacity to perform its service request servicing functionality, said forwarder would take over the function of said owner.

47. The subsystem defined in claim 44, wherein

when a said SVC receives a service request from said host entity, said SVC checks if it is a current owner of service request servicing function;

if it is, then the said SVC services the request;

if the said SVC is not the current owner, then the said SVC conveys to a ownership arbiter a request for ownership transfer to itself, and starts to service said service request after receiving an acknowledgement from said ownership arbiter;

when said ownership arbiter receives said request from the said ownership requester SVC, said ownership arbiter issues a request to a current service request servicing function owner to relinquish ownership, and then said ownership arbiter receives from said current owner an acknowledgement ownership has been relinquished and informs the said ownership requester SVC; and

wherein when said current owner receives said request, said current owner relinquishes ownership at a convenient time and informs said ownership arbiter that ownership has been relinquished.

48. The subsystem defined in claim 44, wherein

when a said SVC receives a service request from said host entity, said SVC checks if it is a current owner of service request servicing function;

if it is, then the said SVC services the request; and

if the said SVC is not the current owner, then the said SVC conveys to a current service request servicing function owner a request for ownership transfer to itself, and then the said SVC becomes a new service request servicing function owner and starts to service said service request after receiving an acknowledgement from said current owner; and

wherein when said current owner receives said request, said current owner would relinquishing ownership at a convenient time and informs the said SVC that ownership has been relinquished.

49. The subsystem of claim 47, wherein if the said SVC is not the current owner, then the said SVC queues all service requests received by it after the said SVC receives said acknowledgement.

50. The subsystem of claim 47, wherein the said SVC checks if there is any service request that were queued before conveying said request for ownership transfer to itself, and if it is, then the said SVC not conveying said request for ownership transfer to itself.

51. The subsystem defined in claim 47, wherein said ownership arbiter decides to whom ownership should be transferred in the event that there are a plurality of concurrent ownership transfer requests from different SVCs.

52. The subsystem of claim 47, wherein said owner relinquishes ownership after all service requests received by it have been serviced to completion.

53. The subsystem of claim 47, wherein said owner prepares for relinquish ownership by queuing any new service requests that may be received during the process and finishing the servicing of any requests currently being serviced.

54. The subsystem defined in claim 53, wherein if there are new Service requests that were queued in the process of relinquishing ownership, said current owner also issues an indication to said ownership arbiter so that ownership of service request servicing function will be restored to it later on.

55. The subsystem defined in claim 48, wherein said current owner conveys updated configuration, state and status information to all the other SVCs in said SVS before the transfer of ownership is complete.

56. The subsystem of claim 48, wherein said current owner decides to whom ownership should be transferred in the event that there are a plurality of concurrent ownership transfer requests from different SVCs.

57. The subsystem defined in claim 56, wherein said current owner forwards the other ownership transfer requests that have been received to said new owner while said current owner informs the selected SVC that ownership has been relinquished.

58. The subsystem defined in claim 56, wherein said current owner informs the other SVCs who is the new owner.

59. The subsystem defined in claim 58, wherein when an ownership transfer requester of the other SVCs receives said information of the new owner, then it conveys to said new owner the request for ownership transfer to itself.

60. A method for dispatching of service requests in a redundant storage virtualization computer system, comprising the steps of:

a host entity selecting only one of a plurality of SVCs redundantly configured to issue service requests at a time; and

said selected SVC receiving service requests from said host entity and servicing them, then returning the results of the servicing of the service requests to said host entity.

61. The method defined in claim 60, wherein said host entity checks if all service requests issued to one of SVCs have been serviced to completion before selecting one of said SVCs to issue service requests.

62. The method defined in claim 60, wherein if said issued service requests have not been serviced to completion, said host entity selects one of said SVCs to issue service requests after said issued service requests have been serviced to completion.

63. The method defined in claim 60, wherein if said issued service requests have not been serviced to completion, said host entity selects said one SVC to issue service request.

64. A method for dispatching of service requests, said method being performed by a host in a redundant storage virtualization computer system, comprising the steps of:

generating a service request;

checking if all issued service requests have been serviced to completion;

issuing said service request to one of redundant SVCs, if all issued service requests have been serviced to completion;

otherwise, said host entity issuing said service request to one of said SVCs after said issued service requests have been serviced to completion.

65. The method defined in claim 64, wherein said host entity random selects any one of said SVCs as a receiving object.

66. A method for dispatching of service requests, said method being performed by a host in a redundant storage virtualization computer system having a plurality of storage virtualization controllers (SVCs) redundantly configured, comprising the steps of:

generating a new service request;

checking if all previously issued service requests have been serviced to completion;

issuing said new service request to one of the SVCs, if all the previously issued service requests have been serviced to completion;

otherwise, said host entity issuing said new service request to the SVC which received said service requests issued previously and not serviced to completion.

67. The method defined in claim 66, wherein said step of issuing said service request if all issued service requests have been serviced to completion further comprises the step of said host entity randomly selecting any one of said SVCs as a receiving object of the new service request.

68. A method for dispatching of service requests in a redundant storage virtualization computer system having a plurality of storage virtualization controllers (SVCs) redundantly configured, comprising the steps of:

a host entity selecting one of redundant SVCs to issue service requests;

said selected SVC receiving service requests from said host entity and checking if it is an owner of service request servicing function; and

,

if it is, then said selected SVC servicing the request; and

,

if it is not, said selected SVC forwarding service requests to an owner of service request servicing function, then said owner receiving and dispatching the service requests for servicing and returning the results of the servicing of the service requests to said host entity.

69. The method defined in claim 68, wherein said owner returns the results of the servicing of the service requests to said host entity through said selected SVC.

70. The method defined in claim 68, further comprising the step of:

any information associated with said service request will be conveyed between said host entity and said owner by first conveying the information to said selected SVC and having said selected SVC forward the information to a destination during said owner servicing service requests.

71. A method for dispatching of service requests, said method being performed by a first SVC in a redundant storage virtualization computer system having a plurality of storage virtualization controllers (SVCs) redundantly configured, comprising the steps of:

receiving a service request from a host entity;

forwarding said service request to a second SVC;

receiving response data and status information of servicing said service request from the second SVC; and

,

forwarding said data and information to said host entity.

72. The method defined in claim 71, wherein before performing the step of forwarding said service request to a second SVC, said first SVC checks if it is an owner of service request servicing function, if it is, then said first SVC services said service request without performing the steps of forwarding said service request to the second SVC and receiving response data and status information of servicing said service request from the second SVC.

73. The method defined in claim 72, further comprising the step of, during servicing service requests, said first SVC conveying information associated with said service request to said host entity and receiving information associated with said service request from said host entity.

74. The method defined in claim 71, further comprising the steps of receiving information associated with said service request from the second SVC and forwarding said information to said host entity, after the step of forwarding said service request to the second SVC.

75. The method defined in claim 71, further comprising the steps of receiving information associated with said service request from said host entity and forwarding said information to the second SVC, after the step of forwarding said service request to the second SVC.

76. A method for dispatching of service requests, said method being performed by a first SVC in a redundant storage virtualization computer system having a plurality of storage virtualization controllers (SVCs) redundantly configured, comprising the steps of:

receiving a service request from a second SVC;

servicing said service request; and

,

issuing response data and status information of servicing said service request to the second SVC.

77. The method defined in claim 76, wherein the step of servicing said service request further comprises the steps of:

conveying information associated with said service request to the second SVC; and

, receiving information associated with said service request from the second SVC.

78. The method defined in claim 76, further comprising the steps of:

receiving a service request from a host entity;

servicing said service request from said host entity; and

,

issuing response data and status information of servicing said service request to said host entity.

79. The method defined in claim 78, wherein the step of servicing said service request from said host entity further comprises:

conveying information associated with said service request to said host entity; and

,

receiving information associated with said service request from said host entity.

80. A method for dispatching of service requests, said method being performed by a SVC in a redundant storage virtualization computer system having a plurality of storage virtualization controllers (SVCs) redundantly configured, comprising the steps of:

receiving a service request from a host entity;

determining whether or not said SVC is a service request servicing function owner;

if said SVC is the service request servicing function owner, servicing the service requests directly; and

,

if said SVC is not the owner, said SVC issuing a request to a service request servicing function ownership arbiter for an ownership transfer to itself, and said SVC servicing the service requests after receiving an acknowledgement from said ownership arbiter.

81. The method defined in claim 80, further comprising the step of, after determining said SVC is not a service request servicing function owner:

said SVC queuing said service requests received.

82. The method defined in claim 81, wherein before the step of said SVC issuing a request for ownership transfer to itself, checks if there is any service request that were queued, and if there is, said SVC not issuing said request for ownership transfer to itself.

83. A method for arbitrating of service request servicing function ownership, said method being performed by a first SVC in a redundant storage virtualization computer system having a plurality of storage virtualization controllers (SVCs) redundantly configured, comprising the steps of:

receiving a request from a second SVC for an ownership transfer;

issuing a request to a service request servicing function owner to relinquish ownership;

receiving an acknowledgement from said owner that ownership has been relinquished; and

,

issuing an acknowledgement to a said SVC to which ownership is to be transferred.

84. The method defined in claim 83, further comprises the step of:

deciding to whom ownership should be transferred.

85. The method defined in claim 83, further comprises the step of:

deciding when a transfer of the function ownership should occur.

86. A method for relinquishing of service request servicing function ownership, said method being performed by a first SVC in a redundant storage virtualization computer system having a plurality of storage virtualization controllers (SVCs) redundantly configured, comprising the steps of:

receiving a request for it to relinquish ownership;

preparing to relinquish ownership at a convenient time; and

,

issuing an acknowledgement to a second SVC issuing said request to inform it that ownership has been relinquished.

87. The method defined in claim 86, wherein the step of preparing to relinquish ownership comprises:

finishing the servicing of any requests currently being serviced; and

,

queuing any new service requests that may be received before issuing the acknowledgement to said second SVC.

88. The method defined in claim 87, further comprises issuing an indication to said entity issuing said request so that ownership of service request servicing function will be restored to it later on.

89. The method defined in claim 86, wherein the step of preparing to relinquish ownership comprises finishing all received service requests.

90. The method defined in claim 86, further comprising the step of:

conveying updated configuration, state and status information to all the other SVCs.

91. The method defined in claim 86, further comprising the step of deciding to whom ownership should be transferred in the event that there are a plurality of concurrent ownership transfer requests from different SVCs.

92. The method defined in claim 91, further comprising the step of forwarding another ownership transfer request that has been received to said decided SVC while informing said decided SVC that ownership has been relinquished.

93. The subsystem defined in claim 86, further comprising the step of informing the other SVCs who is the new owner.