Storage system and storage control method

• US 20070168634A1
• Filed: 03/09/2006
• Published: 07/19/2007
• Est. Priority Date: 01/19/2006
• Status: Abandoned Application

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Eguchi, Yoshiaki, Morishita, Noboru
• Application Number:
  US11/372,962
• Publication Number:
  US 20070168634A1
• Time in Patent Office: Days
• US Class Current: 711/170
• CPC Class Codes: G06F 3/0608 Saving storage space on storage systems
• CPC Class Codes: G06F 3/0631 by allocating resources to storage systems
• CPC Class Codes: G06F 3/0665 at area level, e.g. provisioning of virtual or logical volumes
• CPC Class Codes: G06F 3/0689 Disk arrays, e.g. RAID, JBOD

Abstract

A pool, which has multiple pool regions which are storage regions capable of being dynamically allocated or released, is configured from a plurality of pool groups and a pool free region group which is common to the plurality of pool groups. Each of the pool groups is related to each storage control function of a storage system. When a used value of a certain pool group exceeds the threshold, a storage controller of the storage system selects a pool free region appropriate for the pool group from the pool free region group, and allocates the selected pool free region to the pool group.

Claims

1. A storage system, capable of communicating with one or a plurality of external devices which issue IO commands, the storage system comprising:

a plurality of storage control functions;

a pool having multiple pool regions which are storage regions dynamically allocated or released;

a plurality of virtual volumes which are a plurality of virtual storage devices which are recognized by the external devices and serve as destinations of the IO commands sent from the external devices; and

a storage controller which receives the IO commands sent from the external devices to the virtual volumes, allocates one or more pool regions inside the pool to the virtual volumes, and writes or reads data corresponding to the received IO commands with respect to the allocated one or more pool regions,

wherein the pool comprises a plurality of pool groups which are related to the plurality of storage control functions respectively, and a pool free region group,

each of the plurality of pool groups has a plurality of pool regions,

the pool free region group has a plurality of pool free regions which are pool regions dynamically allocated or released to any of the plurality of pool groups, and is a group common to the plurality of pool groups, and

the storage controller comprises a free allocation portion for allocating the pool free regions inside the common pool free region group to, of the plurality of pool groups, pool groups which satisfy a predetermined allocation condition.

2. The storage system according to claim 1, further comprising:

a storage area which can store a used upper limit which is an upper limit of a value related to capacity of storage capacities of the pool groups, the capacity being actually in use,

wherein, when a used value of a certain pool group of the plurality of pool groups exceeds the used upper limit stored in the storage area of the certain pool group, the free allocation portion allocates at least one pool free region to the certain pool group.

3. The storage system according to claim 1, wherein management on whether or not each of the pool regions in each of the pool groups is already allocated is performed as a separate operation from management of pool regions in other pool groups.

4. The storage system according to claim 1, wherein the free allocation portion selects pool free regions to be allocated to the pool groups in accordance with a predetermined policy.

5. The storage system according to claim 4, wherein

the pool region is a storage region of a certain logical volume of a plurality of logical volumes which are set using physical storage resources that a plurality of RAID groups have,

each of the RAID groups comprises one or a plurality of disk drives,

each of the disk drives can be accessed from the storage controller via each drive path, and

the free allocation portion preferentially allocates pool free regions in the RAID groups and/or drive paths to pool groups, the pool free regions being different from the pool regions which are already allocated to the pool groups.

6. The storage system according to claim 5, wherein the free allocation portion preferentially searches and allocates pool free regions which are different from the allocated pool regions in terms of the drive paths, than pool free regions which are different from the allocated pool regions in terms of the RAID groups.

7. The storage system according to claim 4, wherein

the one or plurality of external devices are a host computer and an external storage system,

the external storage system also has pool regions,

the plurality of storage control functions include an IO processing function for dynamically allocating pool regions in accordance with an IO command from the host computer, and other storage control functions, and

the free allocation portion preferentially allocates pool free regions inside the storage system to pool groups which are related to the IO processing function, and preferentially allocates pool regions inside the external storage system as pool free regions to pool groups corresponding to the other storage control functions.

8. The storage system according to claim 1, wherein the storage controller further comprises a pool region withdrawal portion for causing allocated pool regions to withdraw from a pool group of the plurality of pool groups, which satisfies a predetermined deletion condition, to the common pool free region group.

9. The storage system according to claim 8, further comprising a storage area which can store a used lower limit which is a lower limit of a value related to capacity of storage capacities of the pool groups, the capacity being actually in use,

wherein, when a used value of a certain pool group of the plurality of pool groups is lower than the used lower limit stored in the storage area of the certain pool group, the pool region withdrawal portion causes at least one pool region to withdraw from the certain pool group to the pool free region group.

10. The storage system according to claim 9, wherein when the low value state lasts for a certain period of time, the pool region withdrawal portion causes at least one pool region to withdraw from the certain pool group to the pool free region group.

11. The storage system according to claim 8, wherein the pool region withdrawal portion moves data, which is stored in the pool region to be withdrawn, to other pool region inside the certain pool group.

12. The storage system according to claim 1, wherein the plurality of storage control functions include a function which uses two or more virtual volumes of the plurality of virtual volumes, and different pool groups are related to the two or more virtual volumes respectively.

13. The storage system according to claim 1, wherein the one or plurality of external devices include an external storage system, and the storage controller manages a storage region of the external storage system as a pool region of the storage system, and allocates the pool region of the external storage system to a certain pool group of the plurality of pool groups.

14. A storage control method, wherein, when there exist a pool having multiple pool regions which are storage regions dynamically allocated or released, and a plurality of virtual volumes which are a plurality of virtual storage devices recognized by external devices, which are communication partners, and serve as destinations of IO commands sent from the external devices, and when the pool comprises a plurality of pool groups which are related to a plurality of storage control functions respectively, and a pool free region group, each of the plurality of pool groups has a plurality of pool regions, and the pool free region group has a plurality of pool free regions which are pool regions dynamically allocated or released to any of the plurality of pool groups, and is a group common to the plurality of pool groups, the storage control method comprises the steps of:

receiving the IO commands sent from the external devices to the virtual volumes, allocating one or more pool regions inside the pool to the virtual volumes, and writing or reading data corresponding to the received IO commands with respect to the allocated one or more pool regions; and

allocating the pool free regions inside the common pool free region group to, of the plurality of pool groups, pool groups which satisfy a predetermined allocation condition.

15. The storage control method according to claim 14, wherein, when a used value of a certain pool group of the plurality of pool groups exceeds the used upper limit, which is an upper limit of a value related to capacity of storage capacities of the pool groups, the capacity being actually in use, at least one pool free region is allocated to the certain pool group.

16. The storage control method according to claim 14, wherein management on whether or not each of the pool regions in each of the pool groups is already allocated is performed as a separate operation from management of pool regions in other pool groups.

17. The storage control method according to claim 14, wherein the pool free regions to be allocated to the pool groups are selected in accordance with a predetermined policy.

18. The storage control method according to claim 14, wherein allocated pool regions are caused to withdraw from a pool group of the plurality of pool groups, which satisfies a predetermined deletion condition, to the common pool free region group.

19. The storage control method according to claim 14, wherein the plurality of storage control functions include a function which uses two or more virtual volumes of the plurality of virtual volumes, and different pool groups are related to the two or more virtual volumes respectively.

20. A storage system, capable of communicating with one or a plurality of external devices which issue IO commands, the storage system comprising:

a plurality of storage control functions;

a pool having multiple pool regions which are storage regions dynamically allocated or released;

a plurality of virtual volumes which are a plurality of virtual storage devices which are recognized by the external devices and serve as destinations of the IO commands sent from the external devices; and

a storage controller which receives the IO commands sent from the external devices to the virtual volumes, allocates one or more pool regions inside the pool to the virtual volumes, and writes or reads data corresponding to the received IO commands with respect to the allocated one or more pool regions,

wherein the pool comprises a plurality of pool groups which are related to the plurality of storage control functions respectively, and a pool free region group,

each of the plurality of pool groups has a plurality of pool regions,

the pool free region group has a plurality of pool free regions which are pool regions dynamically allocated or released to any of the plurality of pool groups, and is a group common to the plurality of pool groups,

each RAID group comprises one or a plurality of disk drives,

each disk drive can be accessed from the storage controller via each drive path, and

the storage controller comprises;

a storage area which can store a used upper limit which is an upper limit of a value related to capacity of storage capacities of the pool groups, the capacity being actually in use, and a used lower limit which is a lower limit of a value related to capacity of storage capacities of the pool groups, the capacity being actually in use;

a free allocation portion which, when a used value of a certain pool group of the plurality of pool groups exceeds the used upper limit stored in the storage area of the certain pool group, preferentially searches, from the common pool free region group, pool free regions present in the RAID groups and/or drive paths, the pool free regions being different from the pool regions which are already allocated to the certain pool groups, and allocates the searched pool free regions to the certain pool groups; and

a pool region withdrawal portion which, when a used value of a certain pool group of the plurality of pool groups is lower than the used lower limit stored in the storage area of the certain pool group, moves data, which is stored in at least one pool region to be withdrawn, to other pool region inside the certain pool group, and causes the at least one pool region to withdraw from the certain pool group to the pool free region group.