Network system and method for setting volume group in the network system

A storage network system including at least one lower storage apparatus in which one or more physical devices, each of which has one or more real volumes, are arranged, one or more computers, each being capable of using data in said volumes, for providing data access to the corresponding real volumes, and at least one upper storage apparatus for conducting mediation of the data access, and an administrative server for setting the mediation, a method for setting virtual volume groups through the storage network system, executed by the upper storage apparatus, the method comprising:

• acquiring information on the real volumes, and port information on the physical devices in which the real volumes reside;
• creating virtual volumes being linked to the real volumes, based on the information on the real volumes;
• forming one or more virtual volume groups by combining the virtual volumes, based on the port information, in such a way that the virtual volumes and the virtual volume groups in which the virtual volumes reside have a virtual-volume-to-virtual-volume-group configuration which is identical to a real-volume-to-physical-device configuration of the real volumes and the physical devices in which the real volumes reside;
• and
• establishing the created virtual volume groups in the upper storage apparatus.