Computer system and resource management method

A computer system comprises: a cluster having at least two groups, where one cluster comprises a group containing a plurality of physical servers operating at least one virtual server; at least two cluster management servers which respectively manage the physical servers belonging to each cluster; and an integrated cluster management server which sends and receives information to and from each cluster management server, and manages the cluster management servers in an integrated manner. Each cluster management server collects operating information relating to the virtual servers operated by each physical server belonging to each cluster, and forwards the operating information to the integrated cluster management server. The integrated cluster management server analyzes the operation information relating to the virtual servers, collected by each cluster management server, and on the basis of the analysis results, determines the destination cluster in which a virtual server fulfilling migration conditions is to be disposed.