When the primary cluster for a given protection group fails, the standby cluster in the partnership detects the failure. If the cluster that fails is a member of more than one partnership, multiple failure detections might occur.
The following actions occur when the overall state of a protection group changes to the Unknown state:
Heartbeat failure is detected by a partner cluster.
The heartbeat is activated in emergency mode to verify that the heartbeat loss is not transient and that the primary cluster has failed. The heartbeat remains in the OK state during this default timeout interval, while the heartbeat mechanism continues to retry the primary cluster. Only the heartbeat plug-ins appear in the Error state.
You set this query interval by setting the Query_interval property of the heartbeat. If the heartbeat still fails after four attempts due to the Query_interval that you configured (three retries and one emergency-mode probing), a heartbeat-lost event is generated and logged in the system log. When you specify the default interval, the emergency-mode retry behavior might delay the notification of heartbeat-loss for about nine minutes. Messages are displayed in the GUI and in the output of the geoadm status command.
For more information about logging, see Viewing the Sun Cluster Geographic Edition Log Messages in Sun Cluster Geographic Edition System Administration Guide.