1. A computer system, comprising: at least one storage system including a physical disk for storing data and a disk controller for controlling the physical disk; at least one host computer including a processor, a memory, and an I/O device; and a management computer including a processor, a memory, and an I/O device, which can access the storage system and the host computer, the storage system providing a storage area of the physical disk as at least one logical volume, wherein: the management computer creates a virtual computer within a network segment to which the management computer belongs, the virtual computer including an I/O device that is the same as the I/O device of the host computer in number and type; the management computer defines a connection between the logical volume and the virtual computer; the management computer stores a program in the logical volume connected to the virtual computer; the management computer sets identification information on the host computer in the virtual computer; the management computer releases the connection between the logical volume that stores the program and the virtual computer; and the management computer defines a connection between the logical volume whose connection with the virtual computer has been released and the host computer, whereby the program stored in the logical volume is deployed on the host computer.