See http://www.cubrid.org/cluster. CUBRID Cluster is an open source clustered DBMS for high scalability including global schema, distributed partition and load balancing features. It is a spin-off project from CUBRID project and supported by NHN.
An implementation of a MUD using Java and SQL. It will be fully portable to any JVM, and store the whole MUD in a relational database. Allowing for load balancing and multi server environments and plugins.