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.

       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 10.2.2, "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 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] ...]

       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:

       o  - -help

          Display a help message and exit.

       o  --config-file=file_name

          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.

       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 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

       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. This option was added in MySQL 4.1.6.

       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 username of the MySQL account to use when invoking mysqladmin.

       o  --verbose

          Be more verbose. This option was added in MySQL 4.1.6.

       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 11, "Running Multiple MySQL Servers on the Same

       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 5.5, "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 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.

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

       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:

          # 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 does not matter; you merely 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".

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MySQL 4.1                         11/02/2006                   MYSQLD_MULTI(1)