Slony-I is a "master to multiple slaves" replication system for PostgreSQL supporting cascading and slave promotion. Key features of Slony-I include:
Slony-I can replicate data between different PostgreSQL major versions
Slony-I can replicate data between different hardware or operating systems
Slony-I allows you to only replicate some of the tables to slave
Slony-I allows you to replicate some tables to one slave and other tables to another slave
Slony-I allows different database servers to be the origin(master) for different tables
This book is intended as an administration guide and reference for Slony-I version If you are using a different version of Slony-I then you should refer to the administration guide for that version.