METHOD AND SYSTEM FOR CONSISTENT CLUSTER OPERATIONAL DATA IN A SERVER CLUSTER USING A QUORUM OF REPLICAS

摘要

A method and system for increasing the availability of a server cluster (60sub1-60sub5) while reducing its cost by requiring at a minimum only one node and a quorum replica set (57A) of storage devices (replica members) (58sub-1-58sub2) to form and continue operating as a cluster. A plurality of replica members maintain the cluster operational data and are independent from any given node. A cluster may be formed and continue to operate as long as one server node possesses a quorum (majority) of the replica members. This ensures that a new or surviving cluster has a least one replica member that belonged to the immediately prior cluster and is thus correct with respect to the cluster operational data. Update sequence numbers and/or timestamps are used to determine the most updated replica member from among those in the quorum for reconciling the other replica members.