The Galera Replication Plugin is a synchronous multi-master replication plug-in for MySQL, MariaDB and Percona XtraDB cluster. Galera Replication Plugin features are, for example:
The primary focus of the Galera Replication Plugin is data consistency: the transactions are either applied on every node, or not at all. In short, the Galera Replication Plugin keeps databases synchronized provided that they were properly configured and synchronized at the beginning.
The Galera Replication Plugin differs from the regular MySQL Replication by, for example, addressing a number of issues including write conflicts when writing on multiple masters, replication lag and slaves being out of sync with the master.
See below for an example of a typical Galera Replication cluster:
Galera Replication Cluster
Applications can write to any node in a Galera Replication cluster, and transaction commits (RBR events) are then applied on all servers, through certification-based replication.
Certification-based replication is an alternative approach to synchronous database replication using group communication and transaction ordering techniques.
The minimal recommended Galera Replication cluster consists of three nodes.