I'm going over the vCAC 6.0 documentation for the distributed installation and it's not clear about the implementation requirements for clustered vCAC appliances and their databases.
If you install multiple vCAC appliances and configure them as a cluster, it recommends that you setup an external PostgreSQL cluster "for high availability and failover", but it doesn't say if it's required or not.
Is it possible to setup a clustered vCAC environment without using an external PostgreSQL cluster, or is it a requirement of that configuration?