IP Addressing and Subnets
To configure high-availability (HA), you must consider the subnet that is used by the secondary HA host and the virtual IP address.
Administrators must ensure that the following conditions are met:
The secondary host is in the same subnet as the primary host.
When the IP address of the primary host is reassigned as a cluster virtual IP, the new IP address that you assign must be in the same subnet.
The secondary HA host that you want to add to the HA cluster is not a component in another HA cluster.