Abstract: A failover scope comprises a node collection in a computer cluster. A resource group (e.g., application program) is associated with one or more failover scopes. If a node fails, its hosted resource groups only failover to nodes identified in each resource group's associated failover scope(s), beginning with a first associated failover scope, in order, thereby defining an island of nodes within which a resource group can failover. If unable to failover to a node of a resource group's first failover scope, failover is attempted to a node represented in any next associated failover scope, which may require manual intervention. Failover scopes may represent geographic sites, whereby each resource group attempts to failover to nodes within its site before failing over to another site. Failover scopes may be managed by the cluster runtime automatically, e.g., an added node is detectable as belonging to a site represented by a failover scope.

Abstract: In a server cluster, a system and method is provided for mitigating redundant resource failure notifications and other problems resulting from late handling of messages. Traditional resource management can result in the generation of redundant resource failure notifications that trigger unnecessary recovery actions, or cause other cluster problems such as performing an action that has previously been handled as part of failure recovery. The present invention tracks resource failures and eliminates recovery actions for redundant resource failure notifications. An incarnation number is passed to a resource each time it is called, and is incremented whenever a resource failure notification is delivered. Failure notifications having an incarnation number lower than the current incarnation number are discarded.