The Cassandra noSQL database cluster is used for vSphere Replication Cloud Service replication metadata and configuration storage. vSphere Replication Cloud Service requires client to node encryption contrary to KairosDB, which is used for the optional vCloud Director VM historic performance data. Therefore, a separate Cassandra cluster must be deployed next to the VM Metric Cassandra cluster (if used). For high availability, at least three nodes must be deployed to provide quorum consistency, with a replication factor of 3. A load balancer is not required for accessing the Cassandra database, because vSphere Replication Cloud Service automatically chooses an available node to communicate with. The node discovery is performed through the Platform Services Controller lookup service where each Cassandra node must be registered.