In some situations, a site may have two or more EAM installations that are not clustered (as defined above). The question arises as to whether the separate EAM installations should be connected to a single Couchbase cluster. Assuming the EAM installations are unrelated, perhaps one installation is for production, a second for testing and a third for training, each EAM installation should be connected to its own Couchbase cluster. In a non-production environment with a light load, it might be acceptable to install Couchbase with a single node, without replication.
If Zero Downtime upgrades are contemplated, please see the ZDU documentation for additional considerations.