Disclosed is a system which includes at least one client, a plural number of file servers, each having a file system, and a switch logically arranged between the client and the plural file servers to provide file access services which virtually render the plural file services accessible as a single file system, termed a ‘pseudo file system’, when viewed from the terminal. The switch distributes a command for start of generation of snapshots to the plural file servers, which file servers formulate respective snapshots responsive to the command for start of formation of the snapshots. The switch sets the plural snapshots, generated by the plural file servers, so as to be associated with the file system structure of the virtual file system at the time of formation of the snapshots.