Patent ID: 7925817

Claim:
A computer system comprising: a plurality of servers each comprising a processor, a memory, and an interface; a PCI switch coupled to the plurality of servers via the interfaces; an I/O device coupled to the PCI switch; and a management block for managing a configuration of the PCI switch, wherein: the management block comprises: a switch management block for setting a first access path coupling an active server of the plurality of servers and the I/O device with each other; and a host management block for instructing a standby server, which takes over the active server, of the plurality of servers to make access to the I/O device used by the active server; the switch management block is configured to: set, to the PCI switch, the first access path comprising a first virtual bridge coupling the interface of the active server and a first virtual switch with each other, and a second virtual bridge coupling the I/O device, used by the active server, and the first virtual switch with each other; and set, to the PCI switch, a second access path comprising a third virtual bridge coupling the interface of the standby server and a second virtual switch with each other, and a fourth virtual bridge coupling the I/O device, used by the active server which the standby server takes over, and the second virtual switch with each other, and disable mapping between the I/O device, used by the active server which the standby server takes over, and the fourth virtual bridge of the second access path wherein the host management block instructs, after the second access path is set, the standby server to make access to the fourth virtual bridge coupled to the I/O device, used by the active server which the standby server takes over, the standby server makes access to the fourth virtual bridge coupled to the I/O device, used by the active server which the standby server takes over, according to the instruction from the host management block, and the host management block receives access results from the standby server, and determines, when the access results indicates a failure, that the standby server cannot take over the active server.