SQL Standard /Enterprise. HA configuration is not available on CE version of NMS
Standby server with NMS server software installed and pointing to the same DBs as the primary NMS.
The primary NMS would be installed and run as recommended, with data being stored in a SQL Server DB. In addition, a Standby NMS is installed and pointed at the same SQL Server DB as the primary NMS. The Standby NMS would be fully licensed but the NMS services WOULD NOT be running at this time.
In the event the primary NMS crashes, you immediately redirect Public DNS to the Standby NMS and start the NMS services on the Standby server. This ensures deployed NMS Agentswill connect to the Standby server. DO NOT start the NMS services on the Standby NMS server until after the Primary NMS server is fully shut down, otherwise the cached data in the Standby NMS server would be out of date. It is also a good idea to verify the Standby NMS server is pointing to the proper database..