1. A management server coupled to a server device and one storage device or plural storage devices, comprising: an interface unit coupled to said server device and said one storage device or plural storage devices; a memory device for storing correspondence relationships between physical storage areas and virtual volumes, said physical storage areas being included in said one storage device or plural storage devices, said virtual volumes being virtual storage areas; and a control device for controlling said interface unit and said memory device, wherein said interface unit receives an address of a virtual volume from said server device, and, based on said correspondence relationships stored in said memory device, said control device converts said address of said virtual volume into an address of a physical storage area corresponding thereto, and, said interface unit transmits said address of said physical storage area to a storage device so that said storage device will read out data, said storage device including a storage area indicated by said address of said physical storage area, said data being stored in said storage area.