In an environment where there is a possibility that the user connects from a plurality of blade PCs to the storage, the present invention prevents the data destruction by realizing the exclusive control of the storage device. The storage connection from a blade PC which was possible to connect until now is made to be impossible by that the management server newly generates and sets to the storage device the connection information between the storage device which the blade PC keeps. Further, by sending the newly generated connection information to the other blade PC the connection from that blade PC becomes possible.