With the Failover feature, one central server acts as a Primary server which is used for reporting, configuring alerts, IP groups and other functionalities. A second server, which is the HotStandby Server, does data and configuration replication from the Primary server. This also acts as a mechanism for data backup without shut down of the Primary Server.

Whenever there is a database update or configuration change in the Primary central server, the updates and changes will be automatically updated to the Hotstandby server. It is not possible to view any reports from the Hotstandby server.

In case the Primary server goes down or is inaccessible due to any unknown reason, the HotStandby server will automatically switch to being the Primary server (within a configured time period). Once this happens, all reports and data can be done from this server and there is no data or config loss.

Please refer the following link to know in detail about the Failover feature :
http://www.manageengine.com/products/netflow/distributed-monitoring/help/Failover/failover.html

Regards,
Don Thomas Jacob