vSphere HA isolation address vs DataStore heartbeat

[hp_avik2401]

Hello experts,

I have a vsphere HA cluster configured without a pingable isolation address (gateway is not pingable).

VMware docs says - Isolation address is used by vSphere HA to determine if a host is isolated from the network. vsphere HA uses datastore heartbeating to determine whether the secondary host has failed, is in a network partition, or is network isolated. If the secondary host has stopped datastore heartbeating, it is considered to have failed and its virtual machines are restarted elsewhere.

How does vSphere HA behaves incase of a split brain, while the SAN datastore is still reachable to all hosts?

[depping]

the SAN datastore is used to communicate the state of the environment. if you had an isolation address configured (you can set one outside of the default gateway with an advanced setting) then the isolation address would be pinged, if the ping fails then the host will communicate via the datastore that the host is isolated. the host will then trigger the isolation response (power off for instance) and then the other hosts in the cluster can take action (restart impacted VMs)

[hp_avik2401]

Thanks, what would be the impact on the cluster, if I don't have a isolation address configured ? 

[depping]

If you don't have an isolation address configured then you won't be able to declare an isolation, which means that the workloads will not be powered off when the host is isolated.