mysqld_multi(1)



MYSQLD_MULTI(1)             MariaDB Database System            MYSQLD_MULTI(1)

NAME
       mysqld_multi - manage multiple MariaDB 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.

       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. 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.

       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

       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.)

       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 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 MariaDB account to use when invoking
           mysqladmin. Note that the password value is not optional for this
           option, unlike for other MariaDB programs.

       o   --silent

           Silent mode; disable warnings.

       o   --tcp-ip

           Connect to the MariaDB server(s) via the TCP/IP port instead of the
           UNIX socket. This affects stopping and reporting. If a socket file
           is missing, the server may still be running, but can be accessed
           only via the TCP/IP port. By default connecting is done via the
           UNIX socket. This option affects stop and report operations.

       o   --user=user_name

           The user name of the MariaDB account to use when invoking
           mysqladmin.

       o   --verbose

           Be more verbose.

       o   --version

           Display version information and exit.

       o   --wsrep-new-cluster

           Bootstrap a cluster.

       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.

       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.

       o   Make sure that the MariaDB 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';

           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

COPYRIGHT
       Copyright 2007-2008 MySQL AB, 2008-2010 Sun Microsystems, Inc.,
       2010-2016 MariaDB Foundation

       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 MariaDB Knowledge Base,
       available online at https://mariadb.com/kb/

AUTHOR
       MariaDB Foundation (http://www.mariadb.org/).

MariaDB 10.1                    7 December 2016                MYSQLD_MULTI(1)

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