1. A storage system comprising at least one host computer, at least one storage device for providing a memory device to said host computer, and a management computer for managing said storage device, wherein said management computer comprises: means for acquiring in advance from said host computer storage configuration information that said host computer has; and change notification means for generating change information for changing said storage configuration information that was acquired in advance and posting it to said host computer; and said host computer comprises means for instructing a change of configuration to said storage device based on said change information posted from said management computer.