mysqld_multi
(1)
Name
mysqld_multi - manage multiple MySQL servers
Synopsis
mysqld_multi [options] {start|stop|report} [GNR[,GNR] ...]
Description
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 --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 2.11.1.2, "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 5.3, "Running
Multiple MySQL Instances on One 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]:
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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 --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.
o --example
Display a sample option file.
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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 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.
o --user=user_name
The user name of the MySQL account to use when invoking
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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 5.3,
"Running Multiple MySQL Instances on One 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 6.1.5, "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 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 6.2, "The MySQL Access Privilege System".
You have to do this for each mysqld server. Change the
connection parameters appropriately when connecting to
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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.
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 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 file should probably be in your home dir (~/.my.cnf)
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# 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".
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ATTRIBUTES
See attributes(5) for descriptions of the following
attributes:
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+---------------+-------------------+
|ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+---------------+-------------------+
|Availability | database/mysql-55 |
+---------------+-------------------+
|Stability | Uncommitted |
+---------------+-------------------+
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/).
NOTES
This software was built from source available at
https://java.net/projects/solaris-userland. The original
community source was downloaded from
http://downloads.mysql.com/archives/mysql-5.5/mysql-5.5.31.tar.gz
Further information about this software can be found on the
open source community website at http://dev.mysql.com/.
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