Method for managing storage system using flash memory, and computer

• US 8,909,848 B2
• Filed: 08/24/2009
• Issued: 12/09/2014
• Est. Priority Date: 06/22/2009
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Obana, Manabu, Ohno, Shotaro
• Primary Examiner(s): CARDWELL, ERIC
• Application Number:
  US12/546,395
• Publication Number:
  US 20100325345A1
• Time in Patent Office: 1,933 Days
• US Class Current: 711/103
• CPC Class Codes: G06F 11/108 Parity data distribution in semiconductor storages, e.g. in SSD
• CPC Class Codes: G06F 11/2094 Redundant storage or storage space G06F11/2056 takes precedence
• CPC Class Codes: G06F 2206/1008 Graphical user interface [GUI]
• CPC Class Codes: G06F 2211/1059 Parity-single bit-RAID5, i.e. RAID 5 implementations
• CPC Class Codes: G06F 3/0605 by facilitating the interaction with a user or administrator
• CPC Class Codes: G06F 3/0608 Saving storage space on storage systems
• CPC Class Codes: G06F 3/061 Improving I/O performance
• CPC Class Codes: G06F 3/0616 in relation to life time, e.g. increasing Mean Time Between Failures [MTBF]
• CPC Class Codes: G06F 3/0619 in relation to data integrity, e.g. data losses, bit errors
• CPC Class Codes: G06F 3/0634 by changing the state or mode of one or more devices
• CPC Class Codes: G06F 3/0644 Management of space entities, e.g. partitions, extents, pools
• CPC Class Codes: G06F 3/0647 Migration mechanisms
• CPC Class Codes: G06F 3/0652 Erasing, e.g. deleting, data cleaning, moving of data to a wastebasket
• CPC Class Codes: G06F 3/0653 Monitoring storage devices or systems
• CPC Class Codes: G06F 3/0655 Vertical data movement, i.e. input-output transfer; data movement between one or more hosts and one or more storage devices
• CPC Class Codes: G06F 3/0683 Plurality of storage devices
• CPC Class Codes: G06F 3/0685 Hybrid storage combining heterogeneous device types, e.g. hierarchical storage, hybrid arrays
• CPC Class Codes: G06F 3/0688 Non-volatile semiconductor memory arrays

Abstract

To facilitate the management of a storage system that uses a flash memory as a storage area. A controller of the storage system provided with a flash memory chip manages a surplus capacity value of the flash memory chip, and transmits a value based on the surplus capacity value to a management server, on the basis of at least one of a definition of a parity group, a definition of an internal LU, and a definition of a logical unit. The management server displays a state of the storage system by using the received value based on the surplus capacity value.

Claims

1. An information system, comprising:

a computer;

a storage system, which includes a plurality of flash memory devices and a storage controller coupled to the flash memory devices,

wherein each of the flash memory devices includes a plurality of providing areas and one or more surplus areas, the providing areas are storage areas provided by the flash memory device, and the surplus areas are storage areas used as alternatives to the providing areas when one or more of the providing areas are unused for storing data, and the surplus areas are physically or logically separately secured from the providing areas,

wherein the storage controller is configured to;

(a) define a plurality of logical components using the providing areas of the flash memory devices, with storing relations between the flash memory devices and the logical components being configuration information;

(b) process an I/O request from the computer, comprising converting an address designated by the I/O request to an address of at least one of the logical components and converting the address of the at least one of the logical components to an address of at least one of the flash memory devices, according to the configuration information; and

(c) for each of the flash memory devices, store a surplus capacity value based on a capacity of the surplus areas in the each of the flash memory devices, and

a management system configured to;

(A) receive an operation request, which designates at least one logical component; and

(B) display a management surplus capacity value about the designated logical component, which indicates that a degenerating risk or blockage risk of the designated logical component is increased when the management surplus capacity value becomes close to a defined value,

wherein the management system or the storage controller is configured to calculate the management surplus capacity value by;

(1) selecting one or more flash memory devices among the flash memory devices related to the designated logical component, by referring to the configuration information;

(2) acquiring one or more surplus capacity values corresponding to the one or more flash memory devices selected in the (1); and

(3) statistically calculating the management surplus capacity value, wherein the statistically calculating of the the management surplus capacity value comprising selecting a second smallest value from the one or more surplus capacity values acquired in the (2).

2. The information system according to claim 1, wherein the management system is further configured to:

(C) receive an operation request, which designates a certain flash memory device; and

(D) display a first another management surplus capacity value of the designated flash memory device, which indicates that a blockage risk of the designated flash memory device is increased when the first another management surplus capacity value becomes close to a defined value.

3. The information system according to claim 1,

wherein the computer is configured to define a plurality of computer-side logical components corresponding to the at least one of the logical components defined in the storage system,

wherein the management system is further configured to:

(E) receive an operation request, which designates a certain compute side logical component; and

(F) display a second another management surplus capacity value of the designated computer-side logical component, which indicates that a degenerating or blockage risk of the designated computer-side logical component is increased when the second another management surplus capacity value becomes close to a defined value, and

wherein the second another management surplus capacity value is calculated by he management system, comprising;

(4) selecting one or more logical components among the logical components related to the designated computer-side logical component;

(5) selecting one or more flash memory devices among the flash memory devices related to the selected logical component in the (4), by referring to the configuration information;

(6) acquiring one or more surplus capacity values corresponding to the one or more flash memory devices selected in the (5); and

(7) statistically calculating the second another management surplus capacity value based on the one or more surplus capacity values acquired in the (6).

4. The information system according to claim 3, wherein the plurality of computer side logical component are computer-side LUs.

5. The information system according to claim 1,

wherein the storage controller is configured to dynamically change the relations between the flash memory devices and the logical components, and

wherein, after changing the relation, process (1) considers the changed relation.

6. The information system according to claim 5,

wherein the storage controller is configured to dynamically change the relations autonomously.

7. The information system according to claim 1,

wherein, as the surplus areas are physically or logically separately secured from the providing areas, the surplus area are:

(i) used by a wear leveling technology before the one or more of the providing areas are unused, so that a part of the surplus areas and a part of the providing areas are exchanged, or

(ii) unused by the wear leveling technology before the one or more of the providing areas are unused.

8. The information system according to claim 1,

wherein the displaying information about the designated logical component is to:

(iii) display the management surplus capacity value;

or

(iv) display information indicating that the management surplus capacity value is below the threshold value.

9. A non-transitory computer readable medium having machine instructions stored therein, the instructions when executed by one or more computers of a management system or a storage system,

the storage system including a plurality of flash memory devices and a storage controller coupled to the flash memory devices, wherein each of the flash memory devices includes a plurality of providing areas and one or more surplus areas, the providing areas are storage areas provided by the flash memory device, and the surplus areas are storage areas used as alternatives to the providing areas when one or more of the providing areas are unused for storing data, and the surplus areas are physically or logically separately secured from the providing areas,

cause the one or more computers of the management system or the storage system to perform operations comprising:

(A) receiving an operation request, which designates at least one logical component among a plurality of logical components defined by the storage controller using the providing areas of the flash memory devices; and

(B) displaying a management surplus capacity value about the designated logical component, which indicates that a degenerating risk or blockage risk of the designated logical component is increased when the management surplus capacity value becomes close to a defined value,

wherein the one or more computers of the management system or the storage system are configured to calculate the management surplus capacity value by;

(1) selecting one or more flash memory devices among the flash memory devices related to the designated logical component, by referring to configuration information which indicates relations between the flash memory devices and the logical components;

(2) acquiring one or more surplus capacity values corresponding to the one or more flash memory devices selected in the (1), wherein each of the one or more surplus capacity values is based on a capacity of the surplus areas in the each of the flash memory devices; and

(3) statistically calculating the management surplus capacity value, wherein the statistically calculating of the the management surplus capacity value comprising selecting a second smallest value from the one or more surplus capacity values acquired in the (2).

10. The non-transitory computer readable medium according to claim 9, wherein the one or more computers are further configured to:

(C) receive an operation request, which designates a certain flash memory device; and

(D) display a first another management surplus capacity value of the designated flash memory device, which indicates that a blockage risk of the designated flash memory device is increased when the first another management surplus capacity value becomes close to a defined value.

11. The non-transitor computer readable medium according to claim 9, wherein the one or more computers are further configured to:

(E) receive an operation request, which designates a certain computer-side logical component among a plurality of computer-side logical components that are defined by a computer external to the management system and are corresponding to the at least one of the logical components defined in the storage system; and

(F) display a second another management surplus capacity value of the designated computer-side logical component, which indicates that a degenerating or blockage risk of the designated computer-side logical component is increased when the second another management surplus capacity value becomes close to a defined value, and

wherein the one or more computers of the management system or the storage system are configured to calculate the second another management surplus capacity value by;

(4) selecting one or more logical components among the logical components related to the designated computer-side logical component;

(5) selecting one or more flash memory devices among the flash memory devices related to the selected logical component in the (4), by referring to the configuration information;

(6) acquiring one or more surplus capacity values corresponding to the one or more flash memory devices selected in the (5); and

(7) statistically calculating the second another management surplus capacity value based on the one or more surplus capacity values acquired in the (6).

12. The non-transitory computer readable medium according to claim 11, wherein the plurality of computer side logical component are computer-side LUs.

13. The non-transitory computer readable medium according to claim 9,

wherein the storage controller dynamically changes the relations between the flash memory devices and the logical components, and

wherein, after changing the relation, process (1) considers the changed relation.

14. The non-transitory computer readable medium according to claim 13,

wherein the storage controller dynamically changes the relations autonomously.

15. The non-transitory computer readable medium according to claim 9,

wherein, as the surplus areas are physically or logically separately secured from the providing areas, the surplus area are:

(i) used by a wear leveling technology before the one or more of the providing areas are unused, so that a part of the surplus areas and a part of the providing areas are exchanged, or

(ii) unused by the wear leveling technology before the one or more of the providing areas are unused.

16. The non-transitory computer readable medium according to claim 9,

wherein the displaying information about the designated logical component is to:

(iii) display the management surplus capacity value;

or

(iv) display information indicating that the management surplus capacity value is below he threshold value.

17. An information system, comprising:

a computer;

a storage system, which includes a plurality of flash memory devices and a storage controller coupled to the flash memory devices,

wherein each of the flash memory devices includes a plurality of providing areas and one or more surplus areas, the providing areas are storage areas provided by the flash memory device, and the surplus areas are storage areas used as alternatives to the providing areas when one or more of the providing areas are unused for storing data, and the surplus areas are physically or logically separately secured from the providing areas,

wherein the storage controller is configured to;

(a) define a plurality of logical components using the providing areas of the flash memory devices, with storing relations between the flash memory devices and the logical components being configuration information;

(b) process an I/O request from the computer, comprising converting an address designated by the I/O request to an address of at least one of the logical components and converting the address of the at least one of the logical components to an address of at least one of the flash memory devices, according to the configuration information; and

(c) for each of the flash memory devices, store a surplus capacity value based on a capacity of the surplus areas in the each of the flash memory devices, and

a management system configured to;

(A) receive an operation request, which designates at east one logical component;

(B) display a management surplus capacity value about the designated logical component, which indicates that a degenerating risk or blockage risk of the designated logical component is increased when the management surplus capacity value becomes close to a defined value; and

(C) display a first another management surplus capacity value of a certain flash memory device which is related to the designated logical component, which indicates that a blockage risk of the certain flash memory device is increased when the first another management surplus capacity value becomes close to a defined value,

wherein the management system or the storage controller is configured to calculate the management surplus capacity value by;

(1) selecting one or more flash memory devices among the flash memory devices related to the designated logical component, by referring to the configuration information;

(2) acquiring one or more surplus capacity values corresponding to the one or more flash memory devices selected in the (1); and

(3) statistically calculating the management surplus capacity value based on the one or ore surplus capacity values acquired in the (2).

18. The information system according to claim 17, wherein the (3) statisically calculating the management surplus capacity value comprises calculating a minimum, average, or variance of the one or more surplus capacity values acquired in the (2).

19. The information system according to claim 17, wherein the management system is further configured to:

(D) receive an operation request, which designates a certain flash memory device; and

(E) display a second another management surplus capacity value of the designated flash memory device, which indicates that a blockage risk of the designated flash memory device is increased when the second another management surplus capacity value becomes close to a defined value.

20. The information system according to claim 17,

wherein the computer is configured to define a plurality of computer-side logical components corresponding to the at least one of the logical components defined in the storage system,

wherein the management system is further configured to:

(F) receive an operation request, which designates a certain computer-side logical component; and

(G) display a third another management surplus capacity value of the designated computer-side logical component, which indicates that a degenerating or blockage risk of the designated computer-side logical component is increased when the third another management surplus capacity value becomes close to a defined value, and wherein the third another management surplus capacity value is calculated by the management system, comprising;

(4) selecting one or more logical components among the logical components related to the designated computer-side logical component;

(5) selecting one or more flash memory devices among the flash memory devices related to the selected logical component in the (4), by referring to the configuration information;

(6) acquiring one or more surplus capacity values corresponding to the one or more flash memory devices selected in the (5); and

(7) statistically calculating the third another management surplus capacity value based on the one or more surplus capacity values acquired in the (6).

21. The information system according to claim 20, wherein the plurality of computer side logical component are computer-side LUs.

22. The information system according to claim 17,

wherein the storage controller is configured to dynamically change the relations between the flash memory devices and the logical components, and

wherein, after changing the relation, process (1) considers the changed relation.

23. The information system according to claim 22,

wherein the storage controller is configured to dynamically change the relations autonomously.

24. The information system according to claim 17,

wherein, as the surplus areas are physically or logically separately secured from the providing areas, the surplus area are:

(i) used by a wear leveling technology before the one or more of the providing areas are unused, so that a part of the surplus areas and a part of the providing areas are exchanged, or

(ii) unused by the wear leveling technology before the one or more of the providing areas are unused.

25. The information system according to claim 17,

wherein the displaying information about the designated logical component is to:

(iii) display the management surplus capacity value;

or

(iv) display information indicating that the management surplus capacity value is below the threshold value.

26. An information system, comprising:

a computer;

a storage system, which includes a plurality of flash memory devices and a storage controller coupled to the flash memory devices,

wherein each of the flash memory devices includes a plurality of providing areas and one or more surplus areas, the providing areas are storage areas provided by the flash memory device, and the surplus areas are storage areas used as alternatives to the providing areas when one or more of the providing areas are unused for storing data, and the surplus areas are physically or logically separately secured from the providing areas,

wherein the storage controller is configured to;

(a) define a plurality of logical components using the providing areas of the flash memory devices, with storing relations between the flash memory devices and the logical components being configuration information;

(b) process an I/O request from the computer, comprising converting an address designated by the I/O request to an address of at least one of the logical components and converting the address of the at least one of the logical components to an address of at least one of the flash memory devices, according to the configuration information; and

(c) for each of the flash memory devices, store a surplus capacity value based on a capacity of the surplus areas in the each of the flash memory devices, and

a management system configured to;

(A) receive an operation request, which designates at least one logical component;

(B) display a management surplus capacity value about the designated logical component, which indicates that a degenerating risk or blockage risk of the designated logical component is increased when the management surplus capacity value becomes close to a defined value;

(C) receive an operation request, which designates the storage system; and

(D) display a first another management surplus capacity value of one or more flash memory device for sparing in the designated storage system, indicating that the surplus area of the one or more flash memory device for sparing becomes insufficient, when the first another management surplus capacity value becomes close to a defined value,

wherein the management system or the storage controller is configured to calculate the management surplus capacity value by;

(1) selecting one or more flash memory devices among the flash memory devices related to the designated logical component, by referring to the configuration information;

(2) acquiring one or more surplus capacity values corresponding to the one or more flash memory devices selected in the (1); and

(3) statistically calculating the management surplus capacity value based on the one or more surplus capacity values acquired in the (2).

27. The information system according to claim 26, wherein the (3) statisically calculating the management surplus capacity value comprises calculating a minimum, average, or variance of the one or more surplus capacity values acquired in the (2).

28. The information system according to claim 26, wherein the management system is further configured to:

(E) receive an operation request, which designates a certain flash memory device; and

(F) display a second another management surplus capacity value of the designated flash memory device, which indicates that a blockage risk of the designated flash memory device is increased when the second another management surplus capacity value becomes close to a defined value.

29. The information system according to claim 26,

wherein the computer is configured to define a plurality of computer-side logical components corresponding to the at least one of the logical components defined in the storage system,

wherein the management system is further configured to:

(G) receive an operation request, which designates a certain computer-side logical component; and

(H) display a third another management surplus capacity value of the designated computer-side logical component, which indicates that a degenerating or blockage risk of the designated computer-side logical component is increased when the third another management surplus capacity value becomes close to a defined value, and

wherein the third another management surplus capacity value is calculated by the management system, comprising;

(4) selecting one or more logical components among the logical components related to the designated computer-side logical component;

(5) selecting one or more flash memory devices among the flash memory devices related to the selected logical component in the (4), by referring to the configuration information;

(6) acquiring one or more surplus capacity values corresponding to the one or more flash memory devices selected in the (5); and

(7) statistically calculating the third another management surplus capacity value based on the one or more surplus capacity values acquired in the (6).

30. The information system according to claim 29, wherein the plurality of computer side logical component are computer-side LUs.

31. The information system according to claim 26,

wherein the storage controller is configured to dynamically change the relations between the flash memory devices and the logical components, and

wherein, after changing the relation, process (1) considers the changed relation.

32. The information system according to claim 31,

wherein the storage controller is configured to dynamically change the relations autonomously.

33. The information system according to claim 26,

wherein, as the surplus areas are physically or logically separately secured from the providing areas, the surplus area are:

(i) used by a wear leveling technology before the one or more of the providing areas are unused, so that a part of the surplus areas and a part of the providing areas are exchanged, or

(ii) unused by the wear leveling technology before the one or more of the providing areas are unused.

34. The information system according to claim 26,

wherein the displaying information about the designated logical component is to:

(iii) display the management surplus capacity value;

or

(iv) display information indicating that the management surplus capacity value is below the threshold value.

35. A non-transitory computer readable medium having machine instructions stored therein, the instructions when executed by one or more computers of a management system or a storage system,

the storage system including a plurality of flash memory devices and a storage controller coupled to the flash memory devices, wherein each of the flash memory devices includes a plurality of providing areas and one or more surplus areas, the providing areas are storage areas provided by the flash memory device, and the surplus areas are storage areas used as alternatives to the providing areas when one or more of the providing areas are unused for storing data, and the surplus areas are physically or logically separately secured from the providing areas,

cause the one or more computers of the management system or the storage system to perform operations comprising:

(A) receiving an operation request, which designates at least one logical component among a plurality of logical components defined by the storage controller using the providing areas of the flash memory devices;

(B) displaying a management surplus capacity value about the designated logical component, which indicates that a degenerating risk or blockage risk of the designated logical component is increased when the management surplus capacity value becomes close to a defined value; and

(C) displaying a first another management surplus capacity value of a certain flash memory device which is related to the designated logical component, which indicates that a blockage risk of the certain flash memory device is increased when the first another management surplus capacity value becomes close to a defined value,

wherein the one or more computers of the management system or the storage system are configured to calculate the management surplus capacity value by;

(1) selecting one or more flash memory devices among the flash memory devices related to the designated logical component, by referring to configuration information which indicates relations between the flash memory devices and the logical components;

(2) acquiring one or more surplus capacity values corresponding to the one or more flash memory devices selected in the (1), wherein each of the one or more surplus capacity values is based on a capacity of the surplus areas in the each of the flash memory devices; and

(3) statistically calculating the management surplus capacity value based on the one or more surplus capacity values acquired in the (2).

36. The non-transitory computer readable medium according to claim 35, wherein the one or more computers are further configured to:

(D) receive an operation request, which designates a certain flash memory device; and

(E) display a second another management surplus capacity value of the designated flash memory device, which indicates that a blockage risk of the designated flash memory device is increased when the second another management surplus capacity value becomes close to a defined value.

37. The non-transitory computer readable medium according to claim 35, wherein the one or more computers are further configured to:

(F) receive an operation request, which designates a certain computer-side logical component among a plurality of computer-side logical components that are defined by a computer external to the management system and are corresponding to the at least one of the logical components defined in the storage system; and

(G) display a third another management surplus capacity value of the designated computer-side logical component, which indicates that a degenerating or blockage risk of the designated computer-side logical component is increased when the third another management surplus capacity value becomes close to a defined value, and

wherein the one or more computers of the management system or the storage system are configured to calculate the third another management surplus capacity value by;

(4) selecting one or more logical components among the logical components related to the designated computer-side logical component;

(5) selecting one or more flash memory devices among the flash memory devices related to the selected logical component in the (4), by referring to the configuration information;

(6) acquiring one or more surplus capacity values corresponding to the one or more flash memory devices selected in the (5); and

(7) statistically calculating the third another management surplus capacity value based on the one or more surplus capacity values acquired in the (6).

38. The non-transitory computer readable medium according to claim 37, wherein the plurality of computer side logical component are computer-side LUs.

39. The non-transitory computer readable medium according to claim 35, wherein the (3) statisically calculating the management surplus capacity value comprises calculating a minimum, average, or variance of the one or more surplus capacity values acquired in the (2).

40. The non-transitory computer readable medium according to claim 35,

wherein the storage controller dynamically changes the relations between the flash memory devices and the logical components, and

wherein, after changing the relation, process (1) considers the changed relation.

41. The non-transitory computer readable medium according to claim 40,

wherein the storage controller dynamically changes the relations autonomously.

42. The non-transitory computer readable medium according to claim 35,

wherein, as the surplus areas are physically or logically separately secured from the providing areas, the surplus area are:

(i) used by a wear leveling technology before the one or more of the providing areas are unused, so that a part of the surplus areas and a part of the providing areas are exchanged, or

(ii) unused by the wear leveling technology before the one or more of the providing areas are unused.

43. The non-transitory computer readable medium according to claim 35,

wherein the displaying information about the designated logical component is to:

(iii) display the management surplus capacity value;

or

(iv) display information indicating that the management surplus capacity value is below the threshold value.

44. A non-transitory computer readable medium having machine instructions stored therein, the instructions when executed by one or more computers of a management system or a storage system,

the storage system including a plurality of flash memory devices and a storage controller coupled to the flash memory devices, wherein each of the flash memory devices includes a plurality of providing areas and one or more surplus areas, the providing areas are storage areas provided by the flash memory device, and the surplus areas are storage areas used as alternatives to the providing areas when one or more of the providing areas are unused for storing data, and the surplus areas are physically or logically separately secured from the providing areas,

cause the one or more computers of the management system or the storage system to perform operations comprising:

(A) receiving an operation request, which designates at least one logical component among a plurality of logical components defined by the storage controller using the providing areas of the flash memory devices;

(B) displaying a management surplus capacity value about the designated logical component, which indicates that a degenerating risk or blockage risk of the designated logical component is increased when the management surplus capacity value becomes close to a defined value;

(C) receiving an operation request, which designates the storage system; and

(D) displaying a first another management surplus capacity value of one or more flash memory device for sparing in the designated storage system, indicating that the surplus area of the one or more flash memory device for sparing becomes insufficient, when the first another management surplus capacity value becomes close to a defined value,

wherein the one or more computers of the management system or the storage system are configured to calculate the management surplus capacity value by;

(1) selecting one or more flash memory devices among the flash memory devices related to the designated logical component, by referring to configuration information which indicates relations between the flash memory devices and the logical components;

(2) acquiring one or more surplus capacity values corresponding to the one or more flash memory devices selected in the (1), wherein each of the one or more surplus capacity values is based on a capacity of the surplus areas in the each of the flash memory devices; and

(3) statistically calculating the management surplus capacity value based on the one or more surplus capacity values acquired in the (2).

45. The non-transitory computer readable medium according to claim 44, wherein the one or more computers are further configured to:

(E) receive an operation request, which designates a certain flash memory device; and

(F) display a second another management surplus capacity value of the designated flash memory device, which indicates that a blockage risk of the designated flash memory device is increased when the second another management surplus capacity value becomes close to a defined value.

46. The non-transitory computer readable medium according to claim 44, wherein the one or more computers are further configured to:

(G) receive an operation request, which designates a certain computer-side logical component among a plurality of computer-side logical components that are defined by a computer external to the management system and are corresponding to the at least one of the logical components defined in the storage system; and

(H) display a third another management surplus capacity value of the designated computer-side logical component, which indicates that a degenerating or blockage risk of the designated computer-side logical component is increased when the third another management surplus capacity value becomes close to a defined value, and

wherein the one or more computers of the management system or the storage system are configured to calculate the third another management surplus capacity value by;

(4) selecting one or more logical components among the logical components related to the designated computer-side logical component;

(5) selecting one or more flash memory devices among the flash memory devices related to the selected logical component in the (4), by referring to the configuration information;

(6) acquiring one or more surplus capacity values corresponding to the one or more flash memory devices selected in the (5); and

(7) statistically calculating the third another management surplus capacity value based on the one or more surplus capacity values acquired in the (6).

47. The non-transitory computer readable medium according to claim 46, wherein the plurality of computer side logical component are computer-side LUs.

48. The non-transitory computer readable medium according to claim 44, wherein the (3) statisically calculating the management surplus capacity value comprises calculating a minimum, average, or variance of the one or more surplus capacity values acquired in the (2).

49. The non-transitory computer readable medium according to claim 44,

wherein the storage controller dynamically changes the relations between the flash memory devices and the logical components, and

wherein, after changing the relation, process (1)considers the changed relation.

50. The non-transitory computer readable medium according to claim 49,

wherein the storage controller dynamically changes the relations autonomously.

51. The non-transitory computer readable medium according to claim 44,

wherein, as the surplus areas are physically or logically separately secured from the providing areas, the surplus area are:

(i) used by a wear leveling technology before the one or more of the providing areas are unused, so that a part of the surplus areas and a part of the providing areas are exchanged, or

(ii) unused by the wear leveling technology before the one or more of the providing areas are unused.

52. The non-transitory computer readable medium according to claim 44,

wherein the displaying information about the designated logical component is to:

(iii) display the management surplus capacity value;

or

(iv) display information indicating that the management surplus capacity value is below the threshold value.