Patent ID: 8024532

Claim:
A computer system comprising: a first storage system; and a second storage system coupled to the first storage system, wherein the first storage system comprises a first interface coupled to the second storage system, a first processor coupled to the first interface, and a first memory coupled to the first processor, the first storage system providing a first storage area from and to which data is read and written, wherein the second storage system comprises a second interface coupled to the first storage system, a second processor coupled to the second interface, and a second memory coupled to the second processor, the second storage system providing a second storage area, and wherein the second storage system is configured to: read and write the requested data from and to the first storage area associated with the second storage area when the data is requested to be read from and to be written to the second storage area; specify the first storage area associated with the second storage area from which the data is to be erased upon reception of a request for erasing the data stored in the second storage area; and transmit the request for erasing the data to the first storage system providing the specified first storage area, and wherein the first storage system is configured to erase the data stored in the specified first storage area, based on a data erasure condition included in the request for erasing the data, upon reception of the request for erasing the data.