Tungsten Replicator:
"The Tungsten Replicator implements open source database-neutral master/slave replication. Master/slave replication is a highly flexible technology that can solve a wide variety of problems including the following:
* Availability - Failing over to a slave database if your master database dies
* Performance Scaling - Spreading reads across many copies of data
* Cross-Site Clustering - Maintaining active database replicas across WANs
* Change Data Capture - Extracting changes to load data warehouses or update other systems
* Zero Downtime Upgrade - Performing upgrades on a slave server which then becomes the master"
