After you create a cluster, Host Monitoring enables the vSphere HA master host to respond to host or virtual machine failures and management network isolation.

If Enable Host Monitoring is selected, each host in the cluster is checked to ensure it is running. If a host failure occurs, virtual machines are restarted on another host. Host Monitoring is also required for the vSphere Fault Tolerance recovery process to work properly.


If you need to perform network maintenance that might trigger host isolation responses, VMware recommends that you first suspend vSphere HA by disabling Host Monitoring. After the maintenance is complete, reenable Host Monitoring.