Does anyone know of a DBMS or utility that can proved the following form of replication:

X node on network
a copy of tables on each node
changes can be made on any node
changes must be replicated to all nodes
nodes can be shutdown for indeterminate periods
a dedicated server is not alowed

This is for shared configuration databases for an HMI controlling turbine and compressor trains. Any individual unit may be shutdown. When the unit comes back up, it needs to update its tables with any changes made on another unit.