Patent ID: 7953927

Claim:
A storage system comprising: a first disk device; a first control device coupled with the first disk for controlling the first disk device so as to store data, the first control device including at least a first cache memory; a second disk device; a second control device coupled with the second disk device for controlling the second disk device so as to store data, the second control device including at least a second cache memory; and allocation information including physical resource information of said first disk said first disk device, said second disk device, said first control device, and said second control device, wherein the storage system, by referring to the allocation information, is configured to: accept a first request identifying first capacity to be assigned a first logical partition of said storage system, receive a second request identifying second capacity to be assigned to a second logical partition of said storage system, if the first capacity identified by the first request is smaller than capacity of the first cache memory, then assign the first capacity from the first cache memory to the first logical partition, store remaining capacity of the first cache memory which is capable of being assigned to the first or the second logical partition after the assignment from the first cache memory to the first logical partition, and if the second capacity identified by the second request is larger than said remaining capacity of the first cache memory and is smaller than capacity of the second cache memory, then assign the second capacity from the second cache memory to the second logical partition.