Patent ID: 8046627

Claim:
A computer system group, comprising: a plurality of computer systems; and a failover control unit, wherein the computer systems each comprise: a plurality of servers; a plurality of I/O devices; and one or more I/O switches coupled to the plurality of servers and the plurality of I/O devices, wherein the server can access an external apparatus via any I/O device of one or more I/O devices which are allocated to that server, by means of the I/O switch, and the combination of the servers and I/O devices can be changed in each computer system, and wherein the failover control unit: (1-1) judges whether or not there exists a spare server capable of taking over processing in a computer system having a faulty server which is a current server that has generated a fault; (1-2) searches for another computer system capable of constructing a particular combination corresponding to the combination of the faulty server and the I/O devices allocated thereto, if a judgment result in (1-1) is negative; and (1-3) executes a server switching process, and in this server switching process, performs combination construction processing for constructing the particular combination in the other computer system by allocating particular I/O devices located in the same computer system as the spare server capable of taking over processing which is located in the other computer system, identifier exchange processing for exchanging identifiers of the I/O devices which have been allocated to the faulty server with identifiers allocated to the particular I/O devices, and start-up processing for starting up the spare server capable of taking over processing.