Defining HA

The primary HA Screen manages secondary HA Screens in an HA cluster. A passive HA Screen within an HA cluster mirrors the state of the active Screen, which can be the primary or a secondary HA Screen. When the active Screen fails, the passive Screen that has been running the longest takes over as the active Screen. Primary means the system is the HA administration host for the HA configuration. It does not necessarily mean that the system is the active host

You must use the unique HA interface address for administration. If you use one of the shared addresses, then that address will always resolve to the HA Screen that is currently active. Because the active host is not necessarily the primary administration host, you must use the unique HA interface address to ensure that you are communicating with the correct host.

If you do not use the unique HA interface address, then the connection will be lost and the administration GUI will hang immediately if the remotely administered primary HA Screen is shut down. You will still be able to administer the active HA Screen from the command line, using the command ssadm, but you will be unaware that you are administering a secondary HA Screen. This will not propagate the configuration to any other HA Screen; instead, the configuration will be overwritten when the primary HA Screen comes up again and a policy is activated.