MYSQLD_MULTI(1) 					       MySQL Database System						   MYSQLD_MULTI(1)

NAME

       mysqld_multi - manage multiple MySQL servers

SYNOPSIS

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

DESCRIPTION

       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 2.13.1.2, "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 5.6, "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] ...]

       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 command:

	   shell> mysqld_multi --example

       As of MySQL 5.1.18, 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.)

       Before MySQL 5.1.18, the preceding options are not recognized. Files in the standard locations are read, and any file named by the
       --config-file=file_name option, if one is given. A file named by --config-file is read only for [mysqldN] option groups, not the
       [mysqld_multi] group.

       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.

       As of MySQL 5.1.35, 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. Before MySQL 5.1.35, some versions of mysqld_multi pass the
       --no-defaults options to instances, so these techniques are inapplicable.

       mysqld_multi supports the following options.

       o   --help

	   Display a help message and exit.

       o   --config-file=file_name

	   As of MySQL 5.1.18, this option is deprecated. If given, it is treated the same way as --defaults-extra-file, described earlier.
	   --config-file is removed in MySQL 5.5.

	   Before MySQL 5.1.18, this option specifies the name of an extra option file. It 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.

       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 servers.

       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:

	       [mysqld38]
	       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 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.

       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 5.6, "Running Multiple MySQL Servers on the Same Machine".

       o

	       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 5.3.6, "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 server:

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

	   See Section 5.4, "The MySQL Access Privilege System". 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 allow 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 use --bind-address 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. 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:

	       ----------------------------------------------------------------
	       MY_PWD=`pwd`
	       # 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).

       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 root user.
	   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 file should probably be in your home dir (~/.my.cnf)
	   # or /etc/my.cnf
	   # Version 2.1 by Jani Tolonen
	   [mysqld_multi]
	   mysqld     = /usr/local/bin/mysqld_safe
	   mysqladmin = /usr/local/bin/mysqladmin
	   user       = multi_admin
	   password   = multipass
	   [mysqld2]
	   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
	   [mysqld3]
	   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
	   [mysqld4]
	   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
	   [mysqld6]
	   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 4.2.3.3, "Using Option Files".

COPYRIGHT

       Copyright 2007-2008 MySQL AB, 2008-2010 Sun Microsystems, Inc.

       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
       MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 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 http://www.gnu.org/licenses/.

SEE ALSO

       For more information, please refer to the MySQL Reference Manual, which may already be installed locally and which is also available online
       at http://dev.mysql.com/doc/.

AUTHOR

       Sun Microsystems, Inc. (http://www.mysql.com/).

MySQL 5.1							    04/06/2010							   MYSQLD_MULTI(1)