I have a certain setup, so that two computers are running nearly identical databases: identical setup, tables, users and permissions, only the contents differ. Now I'd like to keep them in sync, WITHOUT an extra machine, hence master-slave setup. The problem is, that either one could fail eventually. Either one or the other machine (with the same database) get data, but not yet both at the same time. This is some sort of load balancing. Is there software out there that "rsyncs" database tables both ways? Or will I have to write scripts for this task? I've already taken a look at Slony but it is unfortunately a "master to multiple slaves". And I want both (or maybe in future three) machines to communicate with each other. That means one gets data, and sends it to other machines running the same db.