On a replication slave, you must establish a unique server ID. If this has not already been done, this part of slave setup requires a server restart.
If the slave server ID is not already set, or the current value
conflicts with the value that you have chosen for the master
server, shut down the slave server and edit the
[mysqld] section of the configuration file to
specify a unique server ID. For example:
After making the changes, restart the server.
If you are setting up multiple slaves, each one must have a
server_id value that
differs from that of the master and from any of the other
If you do not set
(or set it explicitly to its default value of 0), the slave
refuses to connect to a master.
You do not have to enable binary logging on the slave for replication to be set up. However, if you enable binary logging on the slave, you can use the slave's binary log for data backups and crash recovery, and also use the slave as part of a more complex replication topology. For example, where this slave then acts as a master to other slaves.