1, where a master-slave replication.
To copy from a master MySQL server (master) data from another process or multiple MySQL server (slaves) of the primary database DDL and DML operation log transmitted binary copy on the server, and then from the server these logs re-executed so that the main data synchronized from the server.
In MySQL, the copy operation is asynchronous, the server does not need to continuously hold the slaves connected to the received master data server.
MySQL supports one master server simultaneously to multiple copy operations from the server, from the server as the primary server while other servers.