MMM (MySQL Master-Master Replication Manager) is a set of flexible scripts
to perform monitoring/failover and management of MySQL Master-Master
replication configurations (with only one node writable at any time). The
toolset also has the ability to read balance standard master/slave
configurations with any number of slaves, so you can use it to move virtual
IP addresses around a group of servers depending on whether they are behind
in replication. In addition to that, it also has scripts for data backups,
resynchronization between nodes etc.