Patent ID: 7418546

Claim:
A computer system, comprising: a storage subsystem, which has a first interface connected to a network, a first processor connected to the first interface, a first memory connected to the first processor, and a disk drive for storing data requested to be written from the host computer; a host computer connected to the storage subsystem through the network, which has a second interface connected to the network, a second processor connected to the second interface, and a second memory connected to the second processor; and a management computer configured to access the storage subsystem and the host computer which has a third interface connected to the storage subsystem and the host computer, a third processor connected to the third interface, and a third memory connected to the third processor, wherein: the second processor recognizes a storage extent of the disk drive by a storage extent unit; the first processor creates storage extent configuration information containing a correspondence between the storage extent and a group to manage the storage extent by a group unit; and the third processor stores group management information to manage a data protection term for each group, obtains the storage extent configuration information created by the first processor via the third interface, calculates an assigned capacity which is a sum total of capacities of the storage extents assigned to each group based on the obtained storage extent configuration information, forecasts a capacity to be assigned in the future for each group based on the calculated assigned capacity, calculates a protection term expired capacity which is a sum total of capacities of the storage extents storing protection term expired data for each group based on the stored group management information and the obtained storage extent configuration information, and outputs the calculated assigned capacity, the forecast capacity to be assigned in the future, and the calculated protection term expired capacity.