An information processing apparatus transmits, by polling, a status verifying message to a disk array apparatus to verify a status of the disk array apparatus. The disk array apparatus attaches, upon receiving the status verifying message, a request for a command of a process to be executed to a response message to the status verifying message, and transmits the response message to the information processing apparatus. The information processing apparatus creates a command based on the request attached to the response message, and transmits the command created to the disk array apparatus.