Tiered storage pool management and control for loosely coupled multiple storage environment

1. A system comprising:

a first storage system including a first storage controller, which receives input/output (I/O) commands from host computers and provides first storage volumes to the host computers; and

a second storage system including a second storage controller which receives I/O commands from host computers and provides second storage volumes to the host computers;

wherein a first data storing region of one of the first storage volumes is allocated from a first pool by the first storage controller,

wherein a second data storing region of another one of the first storage volumes is allocated from a second pool by the first storage controller,

wherein a third data storing region of one of the second storage volumes is allocated from the first pool by the second storage controller,

wherein a fourth data storing region of another one of the second storage volumes is allocated from the second pool by the second storage controller.

2. The system according to claim 1 ,

wherein allocation of the second data storing region of said another one of the first storage volumes from the first pool by the second storage controller is prohibited.

3. The system according to claim 2 ,

wherein in response to allocation of the second data storing region of said another one of the first storage volumes from the second pool by the first storage controller, the second storage controller subtracts an amount allocated to the first volume from a capacity of the second pool.

4. The system according to claim 1 ,

wherein in response to allocation of the second data storing region of said another one of the first storage volumes from the second pool by the first storage controller, the second storage controller subtracts an amount allocated to the first volume from a capacity of the second pool.

5. The system according to claim 1 ,

wherein the first pool is managed using a plurality of first tiers;

wherein the second pool is managed using a plurality of second tiers; and

wherein a storage media allocated to the second pool, which was allocated to second data storing region, is managed as an independent tier from the plurality of first tiers.

6. The system according to claim 5 ,

wherein the independent tier is determined by network characteristics and access speed of the storage media used.

7. The system according to claim 5 ,

wherein if the storage media is same as a storage media used for the first pool, the storage media used for the first pool has a higher priority as compared to the independent tier.

8. The system according to claim 1 , further comprising:

a management server,

wherein the management server selects to lend capacity from the second pool to the first storage system or change control from the second storage controller to the first storage controller against a storage media which is coupled to both the first and second storage controllers, based on load requirement of the system.

9. The system according to claim 1 , further comprising:

a management server,

wherein the management server selects to lend capacity from the second pool to the first storage system, migrate data from the first storage volume to the second storage volume, or change control from the second storage controller to the first storage controller against a storage media which is coupled to both the first and second storage controllers, based on load requirement of the system.