Starting the Replica

The next step is to tell the replica how to connect to the master and begin replaying its binary logs. You should not use the my.cnf file for this; instead, use the CHANGE MASTER TO statement. This statement replaces the corresponding my.cnf settings completely. It also lets you point the replica at a different master in the future, without stopping the server. Here’s the basic statement you’ll need to run on the replica to start replication:

mysql> CHANGE MASTER TO MASTER_HOST='server1',
    -> MASTER_USER='repl',
    -> MASTER_PASSWORD='p4ssword',
    -> MASTER_LOG_FILE='mysql-bin.000001',
    -> MASTER_LOG_POS=0;

The MASTER_LOG_POS parameter is set to 0 because this is the beginning of the log. After you run this, you should be able to inspect the output of SHOW SLAVE STATUS and see that the replica’s settings are correct: