Patent ID: 8051243

Claim:
An information system comprising: one or more first storage media having first storage characteristics for making up a first pool of capacity of a first tier of storage; one or more second storage media having second storage characteristics for making up a second pool of capacity of a second tier of storage; array groups which are composed of plural storage media including the first storage medium and the second storage medium; thin provisioning pools, including the first pool and the second pool, which are allocated from a portion of the array groups; a provisioning module configured, for a write request directed to a thin provisioning volume of a tier, to generate a new thin provisioning chunk of a corresponding thin provisioning pool of the tier, and allocate the new thin provisioning chunk to an area of the thin provisioning volume if no thin provisioning chunk has been allocated thereto; and a free space management module configured to allocate a new capacity from a corresponding array group to the corresponding thin provisioning pool in order to extend a capacity of the corresponding thin provisioning pool if a used space of the corresponding thin provisioning pool has reached a threshold.