A method and system for selecting a set of systems (nodes) for a server cluster from at least two non-communicating sets of systems. A persistent storage device with cluster configuration information therein is provided as a quorum resource. Using an arbitration process, only one system exclusively reserves the quorum resource. The set with the system therein having the exclusive reservation of the quorum device is selected as the cluster. The arbitration process provides a challenge-defense protocol whereby a system can obtain the reservation of the quorum device when the system that has the reservation fails.