1. A storage system comprising: a primary computer on which at least one application program is executed; a storage apparatus inducing storage of a plurality of data used by the application program on one or a plurality of storage devices; and a secondary computer connected to the primary computer and storage apparatus respectively and controlling allocation of storage areas to the application program; wherein the secondary computer comprises: a device management information management unit for managing device management information related to each storage device; a data management information management unit for managing data management information related to each data; and a control unit for controlling allocation of storage areas to the application programs; and wherein the control unit considers the physical relationship between the requested storage area and already existing other storage areas using the data management information and the device management information when allocation of a storage area to an application program is requested, selects a storage area according to the characteristics of the data stored in the requested storage area, and issues the prescribed instructions to the primary computer and storage apparatus respectively so that the application program can use the selected storage area.