A proposed fail over method for taking over task that is preformed on an active server to a backup server, even when the active server and the backup server have different hardware configuration. The method for making a backup server take over task when a fault occurs on a active server, comprises steps of acquiring configuration information on the hardware in the active server and the backup server, acquiring information relating the hardware in the backup server with the hardware in the active server, selecting a backup server to take over the task that is executed on the active server where the fault occurred, creating logical partitions on the selected backup server, and taking over the task executed on the active server logical partitions, in the logical partitions created on the selected backup server.