An object of this invention is to speed up file access and shorten the switching time upon failure. There is provided a computer system with plural storage systems and plural servers, in which: the storage systems each have a disk drive for storing files read/written by the servers and a storage control device, which has an interface connected to the servers via a network and a controller for controlling file read/write in the disk drive; the storage control device and the servers each have a cache memory, which temporarily stores files read/written by the servers, and a file cache control information unit, which keeps information of files stored in the cache memory; and the file cache control information unit holds information indicating whether or not a file is stored in the cache memory of the storage control device and/or the cache memories of the servers.