Patent ID: 7617411

Claim:
A failover method for a cluster system, the cluster system comprising: first and second virtualization units operated in at least one physical computer; a first system including a guest OS operated in the first virtualization unit and an application operated in the guest OS; a second system including a guest OS operated in the second virtualization unit and an application operated in the guest OS; and a third system capable of starting a new operation when the first system is switched in the second virtualization unit, wherein the cluster system for failing over one of the guest OS and the application between the first system and one of the second system and the third system executes: a first cluster processing operated in each guest OS of monitoring the application in the guest OS and failing over the application between the first system and the second system when a failure occurs; and a second cluster processing operated in each virtualization unit of monitoring the guest OS operated in the virtualization unit and the other virtualization unit, migrating the guest OS and the application of the first system to the third system when a failure occurs, and starting the guest OS and the application to be failed over between the first system and the third system, the failover method for the cluster system comprising the steps of: monitoring one of the guest OS of the first system and the first virtualization unit to detect a failure in the second cluster processing; judging the first cluster processing in the failure-detected guest OS when the failure is detected in the second cluster processing; instructing failover to the judged first cluster processing in the second cluster processing; monitoring a failure of the application in the guest OS in the first cluster processing; failing over the application between the first and second systems when a failure of the application is detected in the first cluster processing; failing over the application and the guest OS between the first and second systems when the failover instruction is obtained in the first cluster processing from the second cluster processing.