Is there a way to stop MySQL Replication on the master?
There does not exist a STOP MASTER; command nor is there a manual mechanism from the Master to stop Replication. You would have to go to each Slave and run on of the following:


STOP SLAVE; (Kills the IO Thread and SQL Thread)
STOP SLAVE IO_THREAD; (Kills the IO Thread only)


Running either of these will get you the following:


Clean Recording of the Replication Coordinates in master.info

Master_Log_File
Read_Master_Log_Pos
Relay_Master_Log_file
Exec_Master_Log_Pos



The IO Thread is what communicates with the Master. Killing the IO Thread on the Master Side using the KILL command would abort the IO Thread on each Slave. That could corrupt the Clean Recording of Replication Coordinates.