A CPU of a performance management server, upon receipt of a request from a keyboard or a mouse to newly assign an application to a specified application server, acquires an I/O path between the requested application server and a storage subsystem combined with the application server from the configuration information managed by the internal database of the performance management server, and based on the performance information managed by the database in the performance management server, an I/O path having the performance information satisfying the designated conditions is extracted from the acquired I/O paths and displayed as a candidate path on a display unit.