Man Pages

mysqld_multi(1) - phpMan mysqld_multi(1) - phpMan

Command: man perldoc info search(apropos)  


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.

       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 5.6,
       "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. (reload is available as
       of MySQL 5.6.3.) 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:

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

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

       ?   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.

       ?   --help

           Display a help message and exit.

       ?   --example

           Display a sample option file.

       ?   --log=file_name

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

       ?   --mysqladmin=prog_name

           The mysqladmin binary to be used to stop servers.

       ?   --mysqld=prog_name

           The mysqld binary to be used. You can specify mysqld_safe as the value for this option. 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

       ?   --no-log

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

       ?   --password=password

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

       ?   --silent

           Silent mode; disable warnings.

       ?   --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.

       ?   --user=user_name

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

       ?   --verbose

           Be more verbose.

       ?   --version

           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 5.6, "Running Multiple MySQL Instances on One
           Machine".

       ?

               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 6.1.5, "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 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> CREATE USER 'multi_admin'@'localhost' IDENTIFIED BY 'multipass';
               mysql> GRANT SHUTDOWN ON *.* TO 'multi_admin'@'localhost';

           See Section 6.2, "The MySQL Access Privilege System". You have to do this for each mysqld server. Change
           the connection parameters appropriately when connecting to each one. 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.

       ?   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.)

       ?   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. 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).

       ?   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_multi]
           mysqld     = /usr/local/mysql/bin/mysqld_safe
           mysqladmin = /usr/local/mysql/bin/mysqladmin
           user       = multi_admin
           password   = my_password
           [mysqld2]
           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
           [mysqld3]
           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
           [mysqld4]
           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
           [mysqld6]
           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 4.2.6, "Using Option Files".

COPYRIGHT
       Copyright (C) 1997, 2016, Oracle and/or its affiliates. All rights reserved.

       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
       Oracle Corporation (http://dev.mysql.com/).



MySQL 5.6                         07/08/2016                   MYSQLD_MULTI(1)