Method for Updating Control Program of Physical Storage Device in Storage Virtualization System and Storage Virtualization Controller and System Thereof

• US 20090313617A1
• Filed: 06/11/2009
• Published: 12/17/2009
• Est. Priority Date: 06/12/2008
• Status: Active Grant

• Current Assignee: Infortrend Technology Incorporated (Infortrend Corporation)
• Original Assignee: Infortrend Technology Incorporated (Infortrend Corporation)
• Inventors: Hung, Ching-Hai
• Granted Patent: US 8,356,292 B2
• Time in Patent Office: Days
• US Class Current: 717/168
• CPC Class Codes: G06F 11/1092 Rebuilding, e.g. when physically replacing a failing disk

Abstract

Method for updating control program of physical storage devices including the steps of: selecting PSD(s) to be updated with the control program; making the PSD(s) in an off-line state; and updating the control program of the PSD(s), wherein if it needs to issue a write request to the selected PSD(s) before completion of updating the control program, unmodified data segment(s) corresponding to the write request is marked as modified data segment(s). the selected PSD(s) performs partial rebuilding after completion of updating the control program, and if it needs to read out from or write to an unmodified data segment of the selected PSD(s) before completion of the partial rebuilding, a R/W request can be issued to the PSD directly without waiting for completion of the partial rebuilding of the PSD. Multiple parity data chunks can also be provided in the same data stripe in another embodiment.

Claims

1. A method for updating a control program of a physical storage device (PSD) in a storage virtualization system, comprising the steps of:

selecting at least one PSD to be updated with a control program thereof;

making the selected PSD enter an off-line state;

updating the control program of the selected PSD, wherein if it needs to issue a write request to the selected PSD before completion of the control program update, an unmodified data segment corresponding to the write request is marked as a modified data segment; and

performing a partial rebuilding on the at least one selected PSD after completion of the control program update, wherein if it needs to read data out from or write data into the unmodified data segment of the selected PSD before completion of the partial rebuilding, a read or write request is issued to the selected PSD directly without waiting for completion of the partial rebuilding of all the modified data segments in the selected PSD.

2. The method as claimed in claim 1, wherein if it needs to read the data out from a data segment of the selected PSD when the selected PSD is in a period of the control program update, redundant data of the data segment is used for computing the read data, and the read data is sent out.

3. The method as claimed in claim 1, wherein if it needs to write data into the modified data segment of the selected PSD, when the selected PSD is in a period of the control program update, the marking of the modified data segment remains unchanged.

4. The method as claimed in claim 1, wherein the partial rebuilding comprises the steps of:

(a) selecting the modified data segment, using redundant data of the modified data segment for computation to obtain new data of the modified data segment, overwriting the modified data segment by the new data, and canceling the marking of the modified data segment; and

(b) repeating step (a) until no modified data segment is existed in the selected PSD.

5. The method as claimed in claim 1, wherein if it needs to read the data out from a modified data segment of the selected PSD when the selected PSD is in a period of the partial rebuilding, redundant data of the modified data segment is used for computing the read data, and the read data is sent out.

6. The method as claimed in claim 1, wherein if it needs to write data into the modified data segment of the selected PSD when the selected PSD is in a period of the partial rebuilding, data in the modified data segment is overwritten by the write data corresponding to the modified data segment, and the marking of the modified data segment is canceled.

7. The method as claimed in claim 1, wherein if it needs to write the data into the modified data segment of the selected PSD when the selected PSD is in a period of the partial rebuilding, the marking of the modified data segment remains unchange.

8. The method as claimed in claim 1, wherein when there occurs a failure of PSD, and a total number of the off-line PSDs in the storage virtualization system is smaller than or equal to a number of parity PSDs, the control program update or the partial rebuilding of the selected PSD is continuously performed until the selected PSD completes the partial building.

9. The method as claimed in claim 1, wherein when there occurs a failure of PSD and a total number of off-line PSDs in the storage virtualization system is equal to a number of parity PSDs, read or write requests that access to the PSDs are temporarily stopped until the selected PSD completes the partial building.

10. The method as claimed in claim 1, wherein when there occurs a failure of PSD and a total number of off-line PSDs in the storage virtualization system is greater than a number of parity PSDs, the data on the modified data segment of the selected PSD is marked as bad data.

11. The method as claimed in claim 1, wherein when there occurs a failure of PSD, the failed PSD is performing the control program update or the partial rebuilding, if the failed PSD has the modified data segment, the marking of the modified data segment is cancelled.

12. The method as claimed in claim 1, wherein if a data linking status of the modified data segment is a status with linked data, the data corresponding to the write request issued to the selected PSD is stored in a memory and becomes a linked data.

13. The method as claimed in claim 12, wherein if it needs to read data out from a data segment of the selected PSD when the selected PSD is in a period of the control program update, redundant data of the data segment is used for computing the read data, and the read data is sent out.

14. The method as claimed in claim 12, wherein if it needs to read data out from the modified data segment of the selected PSD when the selected PSD is in a period of the control program update, the linked data of the modified data segment is directly sent out.

15. The method as claimed in claim 12, wherein if it needs to write data into the unmodified data segment of the selected PSD when the selected PSD is in a period of the control program update, the unmodified data segment is marked as the modified data segment, and the write data of the write request corresponding to the unmodified data segment is stored as the linked data.

16. The method as claimed in claim 12, wherein if it needs to write data into the modified data segment of the selected PSD when the selected PSD is in a period of the control program update, the marking of the modified data segment remains unchanged, and the original linked data linked to the modified data segment is directly overwritten by the write data of the write request corresponding to the modified data segment.

17. The method as claimed in claim 12, wherein the partial rebuilding comprises the steps of:

(a) selecting the modified data segment, duplicating the linked data of the modified data segment to the modified data segment, and canceling the marking of the modified data segment; and

(b) repeating step (a) until no the modified data segment exists in the selected PSD.

18. The method as claimed in claim 12, wherein if it needs to read data out from the modified data segment of the selected PSD when the selected PSD is in a period of the partial rebuilding, the linked data linked to the modified data segment is directly sent out.

19. The method as claimed in claim 12, wherein if it needs to write data into the modified data segment of the selected PSD when the selected PSD is in a period of the partial rebuilding, data in the modified data segment is directly overwritten by the write data of the the write request corresponding to the modified data segment, and the marking of the modified data segment is cancelled.

20. The method as claimed in claim 12, wherein if it needs to write data into the modified data segment of the selected PSD when the selected PSD is in a period of the partial rebuilding, the marking of the modified data segment remains unchanged, and a original linked data linked to the modified data segment is directly overwritten by the write data of the write request corresponding to the modified data segment.

21. The method as claimed in claim 12, wherein when there occurs a failure of PSD and a total number of the failed PSDs in the storage virtualization system is smaller than or equal to a number of parity PSDs, a data loss does not occur, and the control program update or the partial rebuilding of the selected PSD is continuously performed until the selected PSD completes the partial building.

22. The method as claimed in claim 12, wherein when there occurs a failure of PSD and a total number of the failed PSDs in the storage virtualization system is equal to a number of parity PSDs, read or write requests that access to the PSDs are temporarily stopped until the selected PSD completes the partial building.

23. The method as claimed in claim 12, wherein when there occurs a failure of PSD, a total number of the failed PSDs and a number of PSDs that are performing the control program update are greater than a number of parity PSDs, if it needs to issue the read request corresponding the unmodified data segment of the selected PSD, the read request that accesses to the PSD is temporarily stopped until completion of the PSD that are performing the control program update, then redundant data of the unmodified data segment is used for computation the read data, and the read data is sent out.

24. The method as claimed in claim 12, wherein when there occurs a failure of PSD and a total number of the failed PSDs in the storage virtualization system is greater than a number of parity PSDs, the linked data linked to the modified data segment is duplicated to the modified data segment.

25. The method as claimed in claim 12, wherein when there occurs a failure of PSD, the failed PSD is performing the control program update or the partial rebuilding, if the failed PSD has the modified data segment, the marking of the modified data segment is cancelled.

26. The method as claimed in claim 1, wherein the storage virtualization system comprises a plurality of PSDs, a first memory device and a second memory device, wherein each of the PSDs comprises a plurality of data segments and a programmable control program, the first memory device is used for storing the marking of the modified data segment, and the second memory is used for storing a linked data linked to the marking.

27. The method as claimed in claim 26, wherein the first memory device and the second memory device are located in a memory of a redundant array of independent disks (RAID) controller.

28. The method as claimed in claim 27, wherein each of the first memory device and the second memory device is a dynamic random access memory (DRAM) or a non-volatile memory (NVRAM).

29. The method as claimed in claim 28, wherein the NVRAM is a hard disk or SSD or a DRAM to which a battery or a supercapacitor supplies power.

30. The method as claimed in claim 1, wherein the storage virtualization system comprises a plurality of a plurality of PSDs, each of which comprises a plurality of data segments and a programmable control program.

31. The method as claimed in claim 30, wherein the size of each of the data segment in PSD is the size of a data chunk, a cache memory or a logical block.

32. The method as claimed in claim 1, wherein if there is a number N of PSDs in storage virtualization system, and N is a nature number, the control program update for the number N of the PSDs in the system can be simultaneously performed without interrupting read or write requests issued from a host entity to the number N of PSDs.

33. A storage virtualization controller for updating a control program of a PSD in a storage virtualization system, the storage virtualization controller comprising:

a central processing circuitry (CPC);

a host-side IO (input and output) device interconnect controller used to connect the CPC and at least one host entity for receiving an IO request from the at least one host entity; and

a device-side IO device interconnect controller used to connect the CPC and a plurality of PSDs for executing IO operations of the PSDs in response to the IO request received from the at least one host entity, wherein at least one data stripe is provided in the PSDs, and at least one parity data chunk is provided in the same data stripe;

wherein the CPC updates the control program of the PSDs by the following steps, comprising;

selecting at least one PSD to be updated with a control program making the selected PSD enter an off-line state;

updating the control program of the selected PSD, wherein if it needs to issue a write request to the selected PSD before completion of the control program update, an unmodified data segment corresponding to the write request is marked as a modified data segment; and

performing a partial rebuilding on the selected PSD, after completion of the control program update, wherein if it needs to read data out from or write data into an unmodified data segment of the selected PSD before completion of the partial rebuilding, a read request or the write request is issued to the selected PSD directly without waiting for completion of the partial rebuilding of all the modified data segments in the selected PSD.

34. The storage virtualization controller as claimed in claim 33, wherein when there occurs a failure of PSD, and a total number of off-line PSDs in the storage virtualization system is smaller than or equal to a number of parity PSDs, the control program update or the partial rebuilding of the selected PSD is continuously performed until the selected PSD completes the partial building.

35. The storage virtualization controller as claimed in claim 33, wherein when there occurs a failure of PSD, and a total number of off-line PSDs in the storage virtualization system is equal to a number of parity PSDs, read or write requests that access to the PSDs are temporarily stopped until the selected PSD completes the partial building.

36. The storage virtualization controller as claimed in claim 33, wherein if there is a number N of PSDs in storage virtualization system, and the N is a nature number, the control program update for the number N of PSDs in the system can simultaneously be performed without interrupting read or write requests issued from a host entity to the number N of PSDs.

37. The storage virtualization controller as claimed in claim 33, wherein a linking status of the modified data segment is a linked data linked to the modified data segment, and when there occurs a failure of PSD and a total number of the failed PSDs in the storage virtualization system is smaller than or equal to a number of parity PSDs, a data loss will not occur, and the control program update or the partial rebuilding of the selected PSD is continuously performed until the selected PSD completes the partial building.

38. The storage virtualization controller as claimed in claim 33, wherein a linking status of the modified data segment is a linked data linked to the modified data segment, and when there occurs a failure of PSD and a total number of the failed PSDs in the storage virtualization system is equal to a number of parity PSDs, read or write requests that access to the PSDs are temporarily stopped until the selected PSD completes the partial building.

39. A storage virtualization system for updating a control program of a PSD in a storage virtualization system, the storage virtualization system comprising:

a host entity for issuing an IO request;

a storage virtualization controller coupled to the host entity for executing IO operations in response to the IO request; and

a plurality of PSDs coupled to the storage virtualization controller for providing data storage space to the storage virtualization system, wherein at least one data stripe is provided in the plurality of PSDs, and at least one parity data chunks is provided in the same data stripe;

wherein the storage virtualization controller updates the control program of the PSDs by the following steps, comprising;

selecting at least one PSD to be updated with a control program therein;

making the selected PSD enter an off-line state;

updating the control program of the selected PSD, wherein if it needs to issue a write request to the selected PSD before completion of the control program update, an unmodified data segment corresponding to the write request is marked as a modified data segment; and

performing a partial rebuilding on the selected PSD, after completion of the control program update, wherein if it needs to read data out from or write data into an unmodified data segment of the selected PSD before completion of the partial rebuilding, a read request or the write request is issued to the selected PSD directly without waiting for completion of the partial rebuilding of all the modified data segments in the selected PSD.

40. The storage virtualization system as claimed in claim 39, wherein when there occurs a failure of PSD and a total number of off-line PSDs in the storage virtualization system is smaller than or equal to a number of parity PSDs, the control program update or the partial rebuilding of the selected PSD is continuously performed until the selected PSD completes the partial building.

41. The storage virtualization system as claimed in claim 39, wherein when there occurs a failure of PSD and a total number of off-line PSDs in the storage virtualization system is equal to the number of parity PSDs, the read or write requests that access to the PSDs are temporarily stopped until the selected PSD completes the partial building.

42. The storage virtualization system as claimed in claim 39, wherein there is a number N of PSDs in storage virtualization system, and the N is a nature number, the control program update for the number N of PSDs in the system can simultaneously be performed without interrupting read or write requests issued from a host entity to the number N of PSDs.

43. The storage virtualization system as claimed in claim 39, wherein a linking status of the modified data segment is a linked data linked to the modified data segment, and when there occurs a failure of PSD and a total number of failed PSDs in the storage virtualization system is smaller than or equal to the number of parity PSDs, a data loss will not occur and the control program update or the partial rebuilding of the selected PSD is continuously performed until the selected PSD completes the partial building.

44. The storage virtualization system as claimed in claim 39, wherein a linking status of the modified data segment is a linked data linked to the modified data segment, and when there occurs a failure of PSD and a total number of failed PSDs in the storage virtualization system is equal to the number of parity PSDs, read or write requests that access to the PSDs are temporarily stopped until the selected PSD completes the partial building.

45. A method for updating a control program of a PSD in a storage virtualization system, comprising:

providing a plurality of parity data chunks in the same data stripe;

selecting at least one PSD desired to update a control program therein;

making the selected PSD enter an off-line state; and

updating the control program of the selected PSD, wherein if it needs to issue a write request to the selected PSD before the completion of the control program update, an unmodified data segment corresponding to the write request is marked as a modified data segment.

46. The method as claimed in claim 45, wherein if it needs to read the data out from a data segment of the selected PSD when the selected PSD is in a period of the control program update, redundant data of the data segment is used for computing the read data, and the read data is send out.

47. The method as claimed in claim 45, wherein if it needs to write data into the modified data segment of the selected PSD, when the selected PSD is in a period of the control program update, the marking of the modified data segment remains unchanged.

48. The method as claimed in claim 45, further comprises step of:

performing a partial rebuilding on the selected PSD after completion of the control program update.

49. The method as claimed in claim 48, wherein the partial rebuilding comprises the steps of:

(a) selecting the modified data segment, using redundant data of the modified data segment for computation to obtain new data of the modified data segment, overwriting the modified data segment by the new data, and canceling the marking of the modified data segment; and

(b) repeating step (a) until no modified data segment is existed in the selected PSD.

50. The method as claimed in claim 48, wherein if it needs to read the data out from a modified data segment of the selected PSD when the selected PSD is in a period of the partial rebuilding, redundant data of the modified data segment is used for computing the read data, and the read data is send out.

51. The method as claimed in claim 48, wherein if it needs to write data into the modified data segment of the selected PSD when the selected PSD is in a period of the partial rebuilding, data in the modified data segment is overwritten by the write data corresponding to the modified data segment, and the marking of the modified data segment is canceled.

52. The method as claimed in claim 48, wherein if it needs to write the data into the modified data segment of the selected PSD when the selected PSD is in a period of partial rebuilding, the marking of the modified data segment remains unchange.

53. The method as claimed in claim 48, wherein when there occurs a failure of PSD and a total number of the off-line PSDs in the storage virtualization system is smaller than or equal to a number of parity PSDs, the control program update or the partial rebuilding of the selected PSD is continuously performed until the selected PSD completes the partial building.

54. The method as claimed in claim 53, wherein the storage virtualization system is configured a plurality of parity PSD therein, and if there a failure of PSD occurs, and the other PSD is performed in a period of control program update or partial rebuilding, the PSD can still continue performing the control program update or partial rebuilding, and the system will not lose data.

55. The method as claimed in claim 48, wherein when there occurs a failure of PSD and a total number of off-line PSDs in the storage virtualization system is equal to a number of parity PSDs, read or write requests that access to the PSDs are temporarily stopped until the selected PSD completes the partial building.

56. The method as claimed in claim 48, wherein when there occurs a failure of PSD and a total number of off-line PSDs in the storage virtualization system is greater than a number of parity PSDs, the data on the modified data segment of the selected PSD is marked as bad data.

57. The method as claimed in claim 48, wherein when there occurs a failure of PSD and the failed PSD is performing the control program update or the partial rebuilding, if the failed PSD has the modified data segment, the marking of the modified data segment is cancelled.

58. The method as claimed in claim 45, wherein if a data linking status of the modified data segment is a status with linked data, the data corresponding to the write request issued to the selected PSD is stored in a memory and becomes a linked data.

59. The method as claimed in claim 58, wherein if it needs to read data out from a data segment of the selected PSD when the selected PSD is in a period of the control program update, redundant data of the data segment is used for computing the read data, and the read data is send out.

60. The method as claimed in claim 58, wherein if it needs to read data out from the modified data segment of the selected PSD when the selected PSD is in a period of the control program update, the linked data of the modified data segment is directly sent out.

61. The method as claimed in claim 58, wherein if it needs to write data into the unmodified data segment of the selected PSD when the selected PSD is in a period of the control program update, the unmodified data segment is marked as the modified data segment, and the write data of the write request corresponding to the unmodified data segment is stored as the linked data.

62. The method as claimed in claim 58, wherein if it needs to write data into the a modified data segment of the selected PSD when the selected PSD is in a period of the control program update, the marking of the modified data segment remains unchanged, and the original linked data linked to the modified data segment is directly overwritten by the write data of the write request corresponding to the modified data segment.

63. The method as claimed in claim 58, further comprises step of:

performing a partial rebuilding on the selected PSD after completion of the control program update.

64. The method as claimed in claim 63, wherein the partial rebuilding comprises the steps of:

(a) selecting the modified data segment, duplicating the linked data of the modified data segment to the modified data segment, and canceling the marking of the modified data segment; and

(b) repeating step (a) until no the modified data segment exists in the selected PSD.

65. The method as claimed in claim 63, wherein if it needs to read data out from the modified data segment of the selected PSD when the selected PSD is in a period of the partial rebuilding, the linked data linked to the modified data segment is directly sent out.

66. The method as claimed in claim 63, wherein if it needs to write data into the modified data segment of the selected PSD when the selected PSD is in a period of the partial rebuilding, data in the modified data segment is directly overwritten by the write data of the the write request corresponding to the modified data segment, and the marking of the modified data segment is cancelled.

67. The method as claimed in claim 63, wherein if it needs to write data into the data segment of the selected PSD when the selected PSD is in a period of partial rebuilding, the marking of the modified data segment remains unchanged, and a original linked data linked to the modified data segment is directly overwritten by the write data of the write request corresponding to the modified data segment.

68. The method as claimed in claim 63, wherein when there occurs a failure of PSD and a total number of the failed PSDs in the storage virtualization system is smaller than or equal to a number of parity PSDs, a data loss will not occur, and the control program update or the partial rebuilding of the selected PSD is continuously performed until the selected PSD completes the partial building.

69. The method as claimed in claim 63, wherein the storage virtualization system is configured a plurality of parity PSD therein, and if there a failure of PSD occurs, and the other PSD is performed in a period of control program update or partial rebuilding, the PSD can still continue performing the control program update or partial rebuilding and the system will not lose data.

70. The method as claimed in claim 63, wherein when there occurs a failure of PSD, a total number of the failed PSDs is equal to a number of parity PSDs, read or write requests that access to the PSD are temporarily stopped until the selected PSD completes the partial building.

71. The method as claimed in claim 63, wherein when there occurs a failure of PSD, a total number of the failed PSDs and PSDs of control program update is greater than a number of parity PSDs, if it needs to write data into the unmodified data segment of the selected PSD, the read request that access to the PSD is temporarily stopped until the selected PSD completes the control program update, then redundant data of the unmodified data segment is used by computating the read data, and the read data is send out.

72. The method as claimed in claim 63, wherein when there occurs a failure of PSD and a total number of the failed PSDs in the storage virtualization system is greater than a number of parity PSDs, the linked data linked to the modified data segment is duplicated to the modified data segment.

73. The method as claimed in claim 63, wherein when there occurs a failure of PSD and the failed PSD is performing the control program update or the partial rebuilding, if the failed PSD has the modified data segment, the marking of the modified data segment is cancelled.

74. The method as claimed in claim 45 or claim 58, wherein the storage virtualization system comprises a plurality of PSDs, a first memory device and a second memory device, wherein each of the PSDs comprises a plurality of data segments and a programmable control program, the first memory device is used for storing the marking of the modified data segment, and the second memory is used for storing a linked data linked to the marking.

75. The method as claimed in claim 74, wherein the first memory device and the second memory device are located in a memory of a redundant array of independent disks (RAID) controller.

76. The method as claimed in claim 75, wherein each of the first memory device and the second memory device is a dynamic random access memory (DRAM) or a non-volatile memory (NVRAM).

77. The method as claimed in claim 76, wherein the NVRAM is a hard disk or SSD or a DRAM to which a battery or a supercapacitor supplies power thereof.

78. The method as claimed in claim 45 or claim 58, wherein the storage virtualization system comprises a plurality of a plurality of PSDs, each of which comprises a plurality of data segments and a programmable control program.

79. The method as claimed in claim 78, wherein the size of each of the data segment in PSD is the size of a data chunk, a cache memory or a logical block.

80. The method as claimed in claim 45 or claim 58, wherein if there is a number N of PSDs in storage virtualization system, and N is a nature number, the control program update for the number N of the PSDs in the system can be simultaneously performed without interrupting read or write requests issued from a host entity to the number N of PSDs.

81. A storage virtualization controller for updating a control program of a PSD in a storage virtualization system, the storage virtualization controller comprising:

a central processing circuitry (CPC);

a host-side IO device interconnect controller used to connect the CPC and at least one host entity for receiving an IO request from the at least one host entity; and

a device-side IO device interconnect controller used to connect the CPC and a plurality of PSDs for executing IO operations of the PSDs in response to the IO request received from the at least one host entity, wherein at least one data stripes is provided in the PSD and a plurality of parity data chunks are provided in the same data stripe;

wherein the CPC updates the control program of the PSDs by the following steps, comprising;

selecting at least one PSD to be updated with a control program;

making the selected PSD enter an off-line state;

updating the control program of the selected PSD, wherein if it needs to issue a write request to the selected PSD before the completion of the control program update, an unmodified data segment corresponding to the write request is marked as a modified data segment.

82. The storage virtualization controller as claimed in claim 81, wherein when there occurs a failure of PSD and a total number of off-line PSDs in the storage virtualization system is smaller than or equal to a number of parity PSDs, the control program update or the partial rebuilding of the selected PSD is continuously performed until the selected PSD completes the partial building.

83. The storage virtualization controller as claimed in claim 81, wherein a linking status of the modified data segment is a linked data linked to the modified data segment, and when there occurs a failure of PSD and a total number of off-line PSDs in the storage virtualization system is equal to a number of parity PSDs, read or write requests that access to the PSDs are temporarily stopped until the selected PSD completes the partial building.

84. The storage virtualization controller as claimed in claim 81, wherein if there is a number N of PSDs in storage virtualization system, and the N is a nature number, the control program update for the number N of PSDs in the system can simultaneously be performed without interrupting read or write requests issued from a host entity to the number N of PSDs.

85. The storage virtualization controller as claimed in claim 81, wherein a linking status of the modified data segment is a linked data linked to the modified data segment, and when there occurs a failure of PSD and a total number of the failed PSDs in the storage virtualization system is smaller than or equal to a number of parity PSDs, a data loss will not occur and the control program update or the partial rebuilding of the selected PSD is continuously performed until the selected PSD completes the partial building.

86. The storage virtualization controller as claimed in claim 81, wherein a linking status of the modified data segment is a linked data linked to the modified data segment, and when there occurs a failure of PSD and a total number of the failed PSDs in the storage virtualization system is equal to a number of parity PSDs, read or write requests that access to the PSDs are temporarily stopped until the selected PSD completes the partial building.

87. A storage virtualization system for updating a control program of a PSD in a storage virtualization system, the storage virtualization system comprising:

a host entity for issuing an IO request;

a storage virtualization controller coupled to the host entity for executing IO operations in response to the IO request; and

a plurality of PSDs coupled to the storage virtualization controller for providing data storage space to the storage virtualization system, wherein at least one data stripes is provided in the plurality of PSDs and a plurality of parity data chunks are provided in the same data stripe;

wherein the storage virtualization controller updates the control program of the PSDs by the following steps, comprising;

selecting at least one PSD to be updated with a control program therein;

making the selected PSD to enter an off-line state;

updating the control program of the selected PSD, wherein if it needs to issue a write request to the selected PSD before the completion of the control program update, an unmodified data segment corresponding to the write request is marked as a modified data segment.

88. The storage virtualization system as claimed in claim 87, wherein when there occurs a failure of PSD and a total number of off-line PSDs in the storage virtualization system is smaller than or equal to a number of parity PSDs, the control program update or the partial rebuilding of the selected PSD is continuously performed until the selected PSD completes the partial building.

89. The storage virtualization system as claimed in claim 87, wherein when there occurs a failure of PSD and a total number of off-line PSDs in the storage virtualization system is equal to the number of parity PSDs, the read or write requests that access to the PSDs are temporarily stopped until the selected PSD completes the partial building.

90. The storage virtualization system as claimed in claim 87, wherein there is a number N of PSDs in storage virtualization system, and the N is a nature number, the control program update for the number N of PSDs in the system can simultaneously be performed without interrupting read or write requests issued from a host entity to the number N of PSDs.

91. The storage virtualization system as claimed in claim 87, wherein a linking status of the modified data segment is a linked data linked to the modified data segment, and when there occurs a failure of PSD and a total number of failed PSDs in the storage virtualization system is smaller than or equal to the number of parity PSDs, a data loss will not occur and the control program update or the partial rebuilding of the selected PSD is continuously performed until the selected PSD completes the partial building.

92. The storage virtualization system as claimed in claim 87, wherein a linking status of the modified data segment is a linked data linked to the modified data segment, and when there occurs a failure of PSD and a total number of failed PSDs in the storage virtualization system is equal to the number of parity PSDs, read or write requests that access to the PSDs are temporarily stopped until the selected PSD completes the partial building.