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MYSQLD_MULTI(1) | MySQL Database System | MYSQLD_MULTI(1) |
NAME¶
mysqld_multi - manage multiple MySQL serversSYNOPSIS¶
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 [mysqld N] 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|report} [GNR[,GNR] ...]
shell> mysqld_multi start 17
shell> mysqld_multi stop 8,10-13
shell> mysqld_multi --example
•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 [mysqld N] option
groups. The [mysqld_multi] group can be used for options to
mysqld_multi itself. [mysqld N] 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.
•--config-file=file_name
This option is deprecated. If given, it is treated the same way as
--defaults-extra-file, described earlier. --config-file was
removed in MySQL 5.5.3.
•--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. 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 [mysqld N] 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:
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. Note that 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.
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';
•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.
•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 [mysqld
N] 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
COPYRIGHT¶
Copyright © 1997, 2018, 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/).02/25/2018 | MySQL 5.5 |