What’s MySQL Replication
Replication enables data from one MySQL database server (the master) to be replicated to one or more MySQL database servers (the slaves).
So MySQL Master-Master Replication
In other words MySQL replication is the process by which data stored in a database, will be copied to a second server’s database. This is called MySQL master-slave replication. Today I’m going to focus on MySQL master-master replication where it allows data to be copied from either server. In other words perform reads or writes from either server.