You enable Failover support for each Replication Server in your system; once for the RSSD connection, and once for all other database connections from the specified Replication Server to Adaptive Servers.
You cannot enable Failover support for individual connections, except the RSSD connection.
The default for Failover support in Replication Server is “off” for all connections from a Replication Server to Adaptive Servers.
For continuing replication, you should enable Failover support for all connections. However, in some cases you may want to disable connection Failover when the companion server’s workload exceeds its capacity.