A computerized data storage system includes at least one storage device including a nonvolatile writable medium; a cache memory operatively coupled to the storage port and including a data storing area and a data management controller and a storage port. The storage port is operable to connect to a host computer, receive and send I/O information required by the host computer. The storage port is also operable to receive a request to read data, and, in response to the request to read data, the storage port is operable to send the data stored in the data storing area of the cache memory. The storage port is further operable to receive a request to write data, and, in response to the request to write data, the storage port is operable to send the write data to the data storing area of the cache memory. The storage system further includes a thin provisioning controller operable to provide a virtual volume having a virtual volume page, a capacity pool having a capacity pool page and manage a mapping between the virtual volume page and the capacity pool page. The storage system further includes a data compression controller operable to perform a compression operation, and a data decompression controller operable to perform a decompression operation.