A host server of a storage system transmits path information and a simultaneous command issue number to a storage managing server, while the path information corresponds to such paths that when the host server executes an application program, the host server accesses to a logical volume, the simultaneous command issue number corresponds to a total number of commands issued to the respective paths. A storage monitoring agent server transmits to the storage managing server, an upper limit number of command multiplex numbers. When accepting path information, a simultaneous command issue number, and the command multiplex number upper limit value, the storage managing server proportionally distributes the command multiplex number upper limit value of the port to the respective paths so as to calculate a command multiplex upper limit value, and calculated result.