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MYSQLD_MULTI(1)		     MySQL Database System	       MYSQLD_MULTI(1)

       mysqld_multi - manage multiple MySQL servers

       mysqld_multi [options] {start|stop|report} [GNR[,GNR] ...]

       mysqld_multi is designed	to manage several mysqld processes that	listen
       for connections on different Unix socket	files and TCP/IP ports.	It can
       start or	stop servers, or report	their current status.

	   For some Linux platforms, MySQL installation	from RPM or Debian
	   packages includes systemd support for managing MySQL	server startup
	   and shutdown. On these platforms, mysqld_multi is not installed
	   because it is unnecessary. For information about using systemd to
	   handle multiple MySQL instances, see	Section	2.5.10,	"Managing
	   MySQL Server	with systemd".

       mysqld_multi searches for groups	named [mysqldN]	in my.cnf (or in the
       file named by the --defaults-file option).  N can be any	positive
       integer.	This number is referred	to in the following discussion as the
       option group number, or GNR. Group numbers distinguish option groups
       from one	another	and are	used as	arguments to mysqld_multi to specify
       which servers you want to start,	stop, or obtain	a status report	for.
       Options listed in these groups are the same that	you would use in the
       [mysqld]	group used for starting	mysqld.	(See, for example,
       Section 2.10.5, "Starting and Stopping MySQL Automatically".) However,
       when using multiple servers, it is necessary that each one use its own
       value for options such as the Unix socket file and TCP/IP port number.
       For more	information on which options must be unique per	server in a
       multiple-server environment, see	Section	5.7, "Running Multiple MySQL
       Instances on One	Machine".

       To invoke mysqld_multi, use the following syntax:

	   shell> mysqld_multi [options] {start|stop|reload|report} [GNR[,GNR] ...]

       start, stop, reload (stop and restart), and report indicate which
       operation to perform. You can perform the designated operation for a
       single server or	multiple servers, depending on the GNR list that
       follows the option name.	If there is no list, mysqld_multi performs the
       operation for all servers in the	option file.

       Each GNR	value represents an option group number	or range of group
       numbers.	The value should be the	number at the end of the group name in
       the option file.	For example, the GNR for a group named [mysqld17] is
       17. To specify a	range of numbers, separate the first and last numbers
       by a dash. The GNR value	10-13 represents groups	[mysqld10] through
       [mysqld13]. Multiple groups or group ranges can be specified on the
       command line, separated by commas. There	must be	no whitespace
       characters (spaces or tabs) in the GNR list; anything after a
       whitespace character is ignored.

       This command starts a single server using option	group [mysqld17]:

	   shell> mysqld_multi start 17

       This command stops several servers, using option	groups [mysqld8] and
       [mysqld10] through [mysqld13]:

	   shell> mysqld_multi stop 8,10-13

       For an example of how you might set up an option	file, use this

	   shell> mysqld_multi --example

       mysqld_multi searches for option	files as follows:

       o   With	--no-defaults, no option files are read.

       o   With	--defaults-file=file_name, only	the named file is read.

       o   Otherwise, option files in the standard list	of locations are read,
	   including any file named by the --defaults-extra-file=file_name
	   option, if one is given. (If	the option is given multiple times,
	   the last value is used.)

       For additional information about	these and other	option-file options,
       see Section, "Command-Line Options that Affect Option-File

       Option files read are searched for [mysqld_multi] and [mysqldN] option
       groups. The [mysqld_multi] group	can be used for	options	to
       mysqld_multi itself.  [mysqldN] groups can be used for options passed
       to specific mysqld instances.

       The [mysqld] or [mysqld_safe] groups can	be used	for common options
       read by all instances of	mysqld or mysqld_safe. You can specify a
       --defaults-file=file_name option	to use a different configuration file
       for that	instance, in which case	the [mysqld] or	[mysqld_safe] groups
       from that file will be used for that instance.

       mysqld_multi supports the following options.

       o   --help Display a help message and exit.

       o   --example Display a sample option file.

       o   --log=file_name Specify the name of the log file. If	the file
	   exists, log output is appended to it.

       o   --mysqladmin=prog_name The mysqladmin binary	to be used to stop

       o   --mysqld=prog_name The mysqld binary	to be used. Note that you can
	   specify mysqld_safe as the value for	this option also. If you use
	   mysqld_safe to start	the server, you	can include the	mysqld or
	   ledir options in the	corresponding [mysqldN]	option group. These
	   options indicate the	name of	the server that	mysqld_safe should
	   start and the path name of the directory where the server is
	   located. (See the descriptions for these options in
	   mysqld_safe(1).) Example:

	       mysqld =	mysqld-debug
	       ledir  =	/opt/local/mysql/libexec

       o   --no-log Print log information to stdout rather than	to the log
	   file. By default, output goes to the	log file.

       o   --password=password The password of the MySQL account to use	when
	   invoking mysqladmin.	Note that the password value is	not optional
	   for this option, unlike for other MySQL programs.

       o   --silent Silent mode; disable warnings.

       o   --tcp-ip Connect to each MySQL server through the TCP/IP port
	   instead of the Unix socket file. (If	a socket file is missing, the
	   server might	still be running, but accessible only through the
	   TCP/IP port.) By default, connections are made using	the Unix
	   socket file.	This option affects stop and report operations.

       o   --user=user_name The	user name of the MySQL account to use when
	   invoking mysqladmin.

       o   --verbose Be	more verbose.

       o   --version Display version information and exit.

       Some notes about	mysqld_multi:

       o   Most	important: Before using	mysqld_multi be	sure that you
	   understand the meanings of the options that are passed to the
	   mysqld servers and why you would want to have separate mysqld
	   processes. Beware of	the dangers of using multiple mysqld servers
	   with	the same data directory. Use separate data directories,	unless
	   you know what you are doing.	Starting multiple servers with the
	   same	data directory does not	give you extra performance in a
	   threaded system. See	Section	5.7, "Running Multiple MySQL Instances
	   on One Machine".

	       Make sure that the data directory for each server is fully
	       accessible to the Unix account that the specific	mysqld process
	       is started as.  Do not use the Unix root	account	for this,
	       unless you know what you	are doing. See Section 6.1.5, "How to
	       Run MySQL as a Normal User".

       o   Make	sure that the MySQL account used for stopping the mysqld
	   servers (with the mysqladmin	program) has the same user name	and
	   password for	each server. Also, make	sure that the account has the
	   SHUTDOWN privilege. If the servers that you want to manage have
	   different user names	or passwords for the administrative accounts,
	   you might want to create an account on each server that has the
	   same	user name and password.	For example, you might set up a	common
	   multi_admin account by executing the	following commands for each

	       shell> mysql -u root -S /tmp/mysql.sock -p
	       Enter password:
	       mysql> CREATE USER 'multi_admin'@'localhost' IDENTIFIED BY 'multipass';
	       mysql> GRANT SHUTDOWN ON	*.* TO 'multi_admin'@'localhost';

	   See Section 6.2, "Access Control and	Account	Management". You have
	   to do this for each mysqld server. Change the connection parameters
	   appropriately when connecting to each one. Note that	the host name
	   part	of the account name must permit	you to connect as multi_admin
	   from	the host where you want	to run mysqld_multi.

       o   The Unix socket file	and the	TCP/IP port number must	be different
	   for every mysqld. (Alternatively, if	the host has multiple network
	   addresses, you can set the bind_address system variable to cause
	   different servers to	listen to different interfaces.)

       o   The --pid-file option is very important if you are using
	   mysqld_safe to start	mysqld (for example, --mysqld=mysqld_safe)
	   Every mysqld	should have its	own process ID file. The advantage of
	   using mysqld_safe instead of	mysqld is that mysqld_safe monitors
	   its mysqld process and restarts it if the process terminates	due to
	   a signal sent using kill -9 or for other reasons, such as a
	   segmentation	fault.

       o   You might want to use the --user option for mysqld, but to do this
	   you need to run the mysqld_multi script as the Unix superuser
	   (root). Having the option in	the option file	doesn't	matter;	you
	   just	get a warning if you are not the superuser and the mysqld
	   processes are started under your own	Unix account.

       The following example shows how you might set up	an option file for use
       with mysqld_multi. The order in which the mysqld	programs are started
       or stopped depends on the order in which	they appear in the option
       file. Group numbers need	not form an unbroken sequence. The first and
       fifth [mysqldN] groups were intentionally omitted from the example to
       illustrate that you can have "gaps" in the option file. This gives you
       more flexibility.

	   # This is an	example	of a my.cnf file for mysqld_multi.
	   # Usually this file is located in home dir ~/.my.cnf	or /etc/my.cnf
	   mysqld     =	/usr/local/mysql/bin/mysqld_safe
	   mysqladmin =	/usr/local/mysql/bin/mysqladmin
	   user	      =	multi_admin
	   password   =	my_password
	   socket     =	/tmp/mysql.sock2
	   port	      =	3307
	   pid-file   =	/usr/local/mysql/data2/hostname.pid2
	   datadir    =	/usr/local/mysql/data2
	   language   =	/usr/local/mysql/share/mysql/english
	   user	      =	unix_user1
	   mysqld     =	/path/to/mysqld_safe
	   ledir      =	/path/to/mysqld-binary/
	   mysqladmin =	/path/to/mysqladmin
	   socket     =	/tmp/mysql.sock3
	   port	      =	3308
	   pid-file   =	/usr/local/mysql/data3/hostname.pid3
	   datadir    =	/usr/local/mysql/data3
	   language   =	/usr/local/mysql/share/mysql/swedish
	   user	      =	unix_user2
	   socket     =	/tmp/mysql.sock4
	   port	      =	3309
	   pid-file   =	/usr/local/mysql/data4/hostname.pid4
	   datadir    =	/usr/local/mysql/data4
	   language   =	/usr/local/mysql/share/mysql/estonia
	   user	      =	unix_user3
	   socket     =	/tmp/mysql.sock6
	   port	      =	3311
	   pid-file   =	/usr/local/mysql/data6/hostname.pid6
	   datadir    =	/usr/local/mysql/data6
	   language   =	/usr/local/mysql/share/mysql/japanese
	   user	      =	unix_user4

       See Section, "Using Option Files".

       Copyright (C) 1997, 2020, Oracle	and/or its affiliates.

       This documentation is free software; you	can redistribute it and/or
       modify it only under the	terms of the GNU General Public	License	as
       published by the	Free Software Foundation; version 2 of the License.

       This documentation is distributed in the	hope that it will be useful,
       but WITHOUT ANY WARRANTY; without even the implied warranty of
       General Public License for more details.

       You should have received	a copy of the GNU General Public License along
       with the	program; if not, write to the Free Software Foundation,	Inc.,
       51 Franklin Street, Fifth Floor,	Boston,	MA 02110-1301 USA or see

       For more	information, please refer to the MySQL Reference Manual, which
       may already be installed	locally	and which is also available online at

       Oracle Corporation (

MySQL 5.7			  06/02/2020		       MYSQLD_MULTI(1)


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