Once you have added all of the channels you want to use as
replication masters, use a
start replication. When you have enabled multiple channels on a
slave, you can choose to either start all channels, or select a
specific channel to start.
To start all currently configured replication channels:
START SLAVE thread_types;
To start only a named channel, use a
START SLAVE thread_types FOR CHANNEL channel;
thread_types option to choose
specific threads you want the above statements to start on the
slave. See START SLAVE Syntax for more information.