O

Offline

State that applies to a cluster resource, group, or node and marks that object as unavailable. The Cluster Service of an offline node may or may not be running.

Online

State that applies to a cluster resource, group, or node and marks that object as available. When a node is online, it is an active member of the cluster and can own and run groups as well as honor cluster database updates, contribute votes to the quorum algorithm, and maintain heartbeats.