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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. The MySQL
       Instance Manager is an alternative means of managing multiple servers
       (see mysqlmanager(8)).

       mysqld_multi searches for groups named [mysqldN] in my.cnf (or in the
       file named by the --config-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, 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 11, Running Multiple
       MySQL Servers on the Same Machine.

       To invoke mysqld_multi, use the following syntax:

	  shell> mysqld_multi [options] {start|stop|report} [GNR[,GNR] ...]
	  WARNING: Providing a password on command line is insecure as it is
	  visible through /proc to anyone for a short time.

       start, stop, 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 supports the following options:


	  Display a help message and exit.


	  Specify the name of an alternative option file. This affects where
	  mysqld_multi looks for [mysqldN] option groups. Without this option,
	  all options are read from the usual my.cnf file. The option does not
	  affect where mysqld_multi reads its own options, which are always
	  taken from the [mysqld_multi] group in the usual my.cnf file.


	  Display a sample option file.


	  Specify the name of the log file. If the file exists, log output is
	  appended to it.


	  The mysqladmin binary to be used to stop servers.


	  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 pathname of
	  the directory where the server is located. (See the descriptions for
	  these options in mysqld_safe(1).) Example:

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


	  Print log information to stdout rather than to the log file. By
	  default, output goes to the log file.

	 --password=password (INSECURE)

	  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.


	  Silent mode; disable warnings.


	  Connect to each MySQL server via 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 via the TCP/IP port.) By default,
	  connections are made using the Unix socket file. This option affects
	  stop and report operations.


	  The username of the MySQL account to use when invoking mysqladmin.


	  Be more verbose.


	  Display version information and exit.

       Some notes about mysqld_multi:

	 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 11, Running Multiple MySQL Servers on the Same

	 Important: 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 5.5, How to Run
	  MySQL as a Normal User.

	 Make sure that the MySQL account used for stopping the mysqld
	  servers (with the mysqladmin program) has the same username 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 usernames or passwords for the administrative accounts,
	  you might want to create an account on each server that has the same
	  username 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> GRANT SHUTDOWN ON *.*
	      -> TO multi_admin@localhost IDENTIFIED BY multipass;
       See Section 6.2, How the Privilege System Works. You have to do this
       for each mysqld server. Change the connection parameters appropriately
       when connecting to each one. Note that the hostname part of the account
       name must allow you to connect as multi_admin from the host where you
       want to run mysqld_multi.

	 The Unix socket file and the TCP/IP port number must be different
	  for every mysqld.

	 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. Please note that the mysqld_safe script might
	  require that you start it from a certain place. This means that you
	  might have to change location to a certain directory before running
	  mysqld_multi. If you have problems starting, please see the
	  mysqld_safe script. Check especially the lines:

	  # Check if we are starting this relative (for the binary release)
	  if test -d $MY_PWD/data/mysql -a -f ./share/mysql/english/errmsg.sys -a \
	   -x ./bin/mysqld
       The test performed by these lines should be successful, or you might
       encounter problems. See mysqld_safe(1).

	 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 root user.
	  Having the option in the option file doesnt 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 file should probably be in your home dir (~/.my.cnf)
	  # or /etc/my.cnf
	  # Version 2.1 by Jani Tolonen
	  mysqld     = /usr/local/bin/mysqld_safe
	  mysqladmin = /usr/local/bin/mysqladmin
	  user	     = multi_admin
	  password   = multipass
	  socket     = /tmp/mysql.sock2
	  port	     = 3307
	  pid-file   = /usr/local/mysql/var2/hostname.pid2
	  datadir    = /usr/local/mysql/var2
	  language   = /usr/local/share/mysql/english
	  user	     = john
	  socket     = /tmp/mysql.sock3
	  port	     = 3308
	  pid-file   = /usr/local/mysql/var3/hostname.pid3
	  datadir    = /usr/local/mysql/var3
	  language   = /usr/local/share/mysql/swedish
	  user	     = monty
	  socket     = /tmp/mysql.sock4
	  port	     = 3309
	  pid-file   = /usr/local/mysql/var4/hostname.pid4
	  datadir    = /usr/local/mysql/var4
	  language   = /usr/local/share/mysql/estonia
	  user	     = tonu
	  socket     = /tmp/mysql.sock6
	  port	     = 3311
	  pid-file   = /usr/local/mysql/var6/hostname.pid6
	  datadir    = /usr/local/mysql/var6
	  language   = /usr/local/share/mysql/japanese
	  user	     = jani

       See Section 3.2, Using Option Files.

       Copyright 1997-2006 MySQL AB

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       Please email  for more information.

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MySQL 5.0			  12/20/2006		       MYSQLD_MULTI(1)

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