The terms master and slave have historically been used in replication, but the
terms terms primary and replica are now preferred. The old terms are used
still used in parts of the documentation, and in MariaDB commands, although
MariaDB 10.5 has begun the process of renaming. The documentation process is
ongoing. See MDEV-18777 to follow progress on this effort.

Syntax
------

START SLAVE ["connection_name"] [thread_type [, thread_type] ... ] [FOR
CHANNEL "connection_name"]
START SLAVE ["connection_name"] [SQL_THREAD] UNTIL                
  MASTER_LOG_FILE = 'log_name', MASTER_LOG_POS = log_pos [FOR CHANNEL
"connection_name"]
START SLAVE ["connection_name"] [SQL_THREAD] UNTIL
  RELAY_LOG_FILE = 'log_name', RELAY_LOG_POS = log_pos [FOR CHANNEL
"connection_name"]
START SLAVE ["connection_name"] [SQL_THREAD] UNTIL
  MASTER_GTID_POS = <GTID position> [FOR CHANNEL "connection_name"]
START ALL SLAVES [thread_type [, thread_type]]

START REPLICA ["connection_name"] [thread_type [, thread_type] ... ] -- from
10.5.1
START REPLICA ["connection_name"] [SQL_THREAD] UNTIL                
  MASTER_LOG_FILE = 'log_name', MASTER_LOG_POS = log_pos -- from 10.5.1
START REPLICA ["connection_name"] [SQL_THREAD] UNTIL
  RELAY_LOG_FILE = 'log_name', RELAY_LOG_POS = log_pos -- from 10.5.1
START REPLICA ["connection_name"] [SQL_THREAD] UNTIL
  MASTER_GTID_POS = <GTID position> -- from 10.5.1
START ALL REPLICAS [thread_type [, thread_type]] -- from 10.5.1

thread_type: IO_THREAD | SQL_THREAD

Description
-----------

START SLAVE (START REPLICA from MariaDB 10.5.1) with no thread_type options
starts both of the replica threads (see replication). The I/O thread reads
events from the primary server and stores them in the relay log. The SQL
thread reads events from the relay log and executes them. START SLAVE requires
the SUPER privilege, or, from MariaDB 10.5.2, the REPLICATION SLAVE ADMIN
privilege.

If START SLAVE succeeds in starting the replica threads, it returns without
any error. However, even in that case, it might be that the replica threads
start and then later stop (for example, because they do not manage to connect
to the primary or read its binary log, or some other problem). START SLAVE
does not warn you about this. You must check the replica's error log for error
messages generated by the replica threads, or check that they are running
satisfactorily with SHOW SLAVE STATUS (SHOW REPLICA STATUS from MariaDB
10.5.1).

START SLAVE UNTIL
-----------------

START SLAVE UNTIL refers to the SQL_THREAD replica position at which the
SQL_THREAD replication will halt. If SQL_THREAD isn't specified both threads
are started.

START SLAVE UNTIL master_gtid_pos=xxx is also supported. See Global
Transaction ID/START SLAVE UNTIL master_gtid_pos=xxx for more details.

connection_name
---------------

If there is only one nameless primary, or the default primary (as specified by
the default_master_connection system variable) is intended, connection_name
can be omitted. If provided, the START SLAVE statement will apply to the
specified primary. connection_name is case-insensitive.

MariaDB starting with 10.7.0
----------------------------
The FOR CHANNEL keyword was added for MySQL compatibility. This is identical
as using the channel_name directly after START SLAVE.

START ALL SLAVES
----------------

START ALL SLAVES starts all configured replicas (replicas with master_host not
empty) that were not started before. It will give a note for all started
connections. You can check the notes with SHOW WARNINGS.

START REPLICA
-------------

MariaDB starting with 10.5.1
----------------------------
START REPLICA is an alias for START SLAVE from MariaDB 10.5.1.

URL: https://mariadb.com/kb/en/start-replica/