Clustering plus RDBMS change

Hi, I’ve had an existing system up and running on the embedded db for over a year now. For DR purposes, we need a peer in a different geographic location (which I’ll do by using the Clustering plugin - hazelcast). I’d like to do the following:

  1. Deploy new instance in DR datacenter, with postgresql as the backend on the DR instance

  2. Enable clustering on both servers

  3. Finish

The question is “Does a clustered openfire environment require that all instances which are part of the cluster share the same kind of database backend, or can they be heterogeneous (ie: one hsqldb, one postgres)?”

If, as I fear, they must be homogeneous, then what is the preferred/supported way to migrate from hsqldb to postgres?

Thanks in advance!

Chris