Slony-I is a "master to multiple slaves" replication system with cascading
and failover.

The big picture for the development of Slony-I is a master-slave system that
includes all features and capabilities needed to replicate large databases to
a reasonably limited number of slave systems.

Slony-I is a system for data centers and backup sites, where the normal mode
of operation is that all nodes are available.

Homepage:
http://main.slony.info/
