In global clusters, the "health" of the remote clusters is monitored and maintained by the wide-area connector process. The connector process uses heartbeats, such as ICMP, to monitor the state of remote clusters. The state is then communicated to HAD, which then uses the information to take appropriate action when required. For example, when a cluster is shut down gracefully, the connector transitions its local cluster state to exiting and notifies the remote clusters of the new state. When the cluster exits and the remote connectors lose their TCP/IP connection to it, each remote connector transitions their view of the cluster to exited.
To enable wide-area network heartbeats, the wide-area connector process must be up and running. For wide-area connectors to connect to remote clusters, at least one heartbeat to the specified cluster must report the state as alive.
There are three hearbeat states for remote clusters: hbunknown, hbalive, and hbdead.
The following table provides a list of VCS remote cluster states and their descriptions.
See Examples of system state transitions.