Patent ID: 7809977

Claim:
In a computer system in which a plurality of computers are connected to a plurality of I/O devices for connecting with external devices via one or a plurality of I/O switches, an I/O device switching method of allocating one or plurality of arbitrary I/O devices to the computers and changing the allocation, wherein: an I/O device management table that manages a plurality of types of I/O devices connectable to the I/O switches is provided, one or plurality of I/O devices not allocated to the computers are defined and registered as standby I/O devices in the I/O device management table, and when a failure occurs in any one of the I/O devices, the I/O device management table is consulted to select I/O device of the same type as the I/O device in which the failure has occurred, from among the standby I/O devices, and allocate it to a computer to which the I/O device in which the failure has occurred is connected, an I/O switch management table, corresponding to an I/O switch identifier specific to each of the I/O switches, is provided in a management server for managing a port number of an I/O switch, information indicating the type of a device connected to a port, a device identifier specific to each of the I/O devices, and information indicating a state of an I/O device, the management server consults the I/O switch management table to acquire the device identifier of an I/O device in which a failure has occurred, and allocates an I/O device selected in an I/O device selecting unit to a computer to which an I/O device in which a failure has occurred, and when the I/O device management table, corresponding to the identifier of an I/O switch, registers and manages a port number, and information indicating an allocation state of an I/O device, the management server changes an allocation state of an I/O device.