A computer system including a management computer for managing the entire system, an integral apparatus, and a high-level connecting device for connecting the management computer and the integral apparatus is designed so that the management computer retains integral apparatus internal configuration information, configuration information about an integral apparatus to be introduced, that indicates the configuration of the integral apparatus that may possibly be introduced to the system, and lifetime information indicating lifetime of the integral apparatus; obtains connectivity guarantee information indicating whether connectivity between the computer and the storage apparatus is guaranteed or not; selects an integral apparatus to be removed from the system by referring to the lifetime information; selects an integral apparatus to be introduced to the system by referring to the integral apparatus internal configuration information, the configuration information about the integral apparatus to be introduced, and the connectivity guarantee information.