Proper seeding of the cluster and the use of low priority heartbeat cluster interconnect links are best practices with or without the use of I/O fencing. Best practice also recommends multiple cluster interconnect links between systems in the cluster. This allows GAB to differentiate between:

• A loss of all heartbeat links simultaneously, which is interpreted as a system failure. In this case, depending on failover configuration, HAD may attempt to restart the services that were running on that system on another system.

• A loss of all heartbeat links over time, which is interpreted as an interconnect failure. In this case, the assumption is made that there is a high probability that the system is not down, and HAD does not attempt to restart the services on another system.