A server includes a monitoring unit that monitors operation states of one or more physical servers in use on which same applications operate, a synchronization unit that synchronizes the data between one of the physical servers in use and one of virtual servers in a standby physical server, and a switching unit that, when the monitoring unit has detected that a failure has occurred in the operation of one of the physical servers in use, that operates a second application of the same applications while referring to a piece of the data on the one of the virtual servers synchronized by the synchronization unit with the data on the one of the physical servers in use, and that switches operation from the one of the virtual servers to the standby physical server.