Slony-I is enterprise-level "master to multiple slaves" replication system with cascading and failover. The big picture for the development of Slony-I is to build 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 developed as a system for data centers and backup sites, where the normal mode of operation is that all nodes are available. Differences from 1.2 stream - Removal of TABLE ADD KEY - It drops all support for databases prior to PostgreSQL version 8.3.