MARIADBD-MULTI(1) MariaDB Database System MARIADBD-MULTI(1)

mariadbd-multi - manage multiple MariaDB servers (mariadbd-multi is now a symlink to mariadbd-multi)

mariadbd-multi [options] {start|stop|report} [GNR[,GNR] ...]

mariadbd-multi is designed to manage several mariadbd 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.

mariadbd-multi searches for groups named [mariadbdN] 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 mariadbd-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 [mariadbd] group used for starting mariadbd. 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 mariadbd-multi, use the following syntax:

shell> mariadbd-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, mariadbd-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 [mariadbd17] is 17. To specify a range of numbers, separate the first and last numbers by a dash. The GNR value 10-13 represents groups [mariadbd10] through [mariadbd13]. 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 [mariadbd17]:

shell> mariadbd-multi start 17

This command stops several servers, using option groups [mariadbd8] and [mariadbd10] through [mariadbd13]:

shell> mariadbd-multi stop 8,10-13

For an example of how you might set up an option file, use this command:

shell> mariadbd-multi --example

mariadbd-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 [mariadbd-multi] and [mariadbdN] option groups. The [mariadbd-multi] group can be used for options to mariadbd-multi itself. [mariadbdN] groups can be used for options passed to specific mariadbd instances.

The [mariadbd] or [mariadbd_safe] groups can be used for common options read by all instances of mariadbd or mariadbd_safe. You can specify a --defaults-file=file_name option to use a different configuration file for that instance, in which case the [mariadbd] or [mariadbd_safe] groups from that file will be used for that instance.

mariadbd-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.

•--mariadb-admin=prog_name

The mariadb-admin binary to be used to stop servers.

•--mariadbd=prog_name

The mariadbd binary to be used. Note that you can specify mariadbd_safe as the value for this option also. If you use mariadbd_safe to start the server, you can include the mariadbd or ledir options in the corresponding [mariadbdN] option group. These options indicate the name of the server that mariadbd_safe should start and the path name of the directory where the server is located. (See the descriptions for these options in mariadbd_safe(1).) Example:

[mariadbd38]
mariadbd = mariadbd-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 MariaDB account to use when invoking mariadb-admin. Note that the password value is not optional for this option, unlike for other MariaDB programs.

•--silent

Silent mode; disable warnings.

•--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.

•--user=user_name

The user name of the MariaDB account to use when invoking mariadb-admin.

•--verbose

Be more verbose.

•--version

Display version information and exit.

•--wsrep-new-cluster

Bootstrap a cluster.

Some notes about mariadbd-multi:

•Most important: Before using mariadbd-multi be sure that you understand the meanings of the options that are passed to the mariadbd servers and why you would want to have separate mariadbd processes. Beware of the dangers of using multiple mariadbd 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.
•Important: Make sure that the data directory for each server is fully accessible to the Unix account that the specific mariadbd process is started as. Do not use the Unix root account for this, unless you know what you are doing.
•Make sure that the MariaDB account used for stopping the mariadbd servers (with the mariadbadmin 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> mariadb -u root -S /tmp/mariadb.sock -p
Enter password:
mariadb> 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 mariadbd-multi.

•The Unix socket file and the TCP/IP port number must be different for every mariadbd. (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 mariadbd-safe to start mariadbd (for example, --mariadbd=mariadbd-safe) Every mariadbd should have its own process ID file. The advantage of using mariadbd-safe instead of mariadbd is that mariadbd-safe monitors its mariadbd 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 mariadbd-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 mariadbd-multi. If you have problems starting, please see the mariadbd-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/mariadb -a \
   -f ./share/mariadb/english/errmsg.sys -a \
   -x ./bin/mariadbd
----------------------------------------------------------------

The test performed by these lines should be successful, or you might encounter problems. See mariadbd-safe(1).

•You might want to use the --user option for mariadbd, but to do this you need to run the mariadbd-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 mariadbd processes are started under your own Unix account.

The following example shows how you might set up an option file for use with mariadbd-multi. The order in which the mariadbd 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 [mariadbdN] 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
[mariadbd-multi]
mariadbd     = /usr/local/bin/mariadbd-safe
mariadb-admin = /usr/local/bin/mariadb-admin
user       = multi_admin
password   = multipass
[mariadbd2]
socket     = /tmp/mariadb.sock2
port       = 3307
pid-file   = /usr/local/mysql/var2/hostname.pid2
datadir    = /usr/local/mysql/var2
language   = /usr/local/share/mariadb/english
user       = john
[mariadbd3]
socket     = /tmp/mysql.sock3
port       = 3308
pid-file   = /usr/local/mysql/var3/hostname.pid3
datadir    = /usr/local/mysql/var3
language   = /usr/local/share/mariadb/swedish
user       = monty
[mariadbd4]
socket     = /tmp/mysql.sock4
port       = 3309
pid-file   = /usr/local/mysql/var4/hostname.pid4
datadir    = /usr/local/mysql/var4
language   = /usr/local/share/mariadb/estonia
user       = tonu
[mariadbd6]
socket     = /tmp/mysql.sock6
port       = 3311
pid-file   = /usr/local/mysql/var6/hostname.pid6
datadir    = /usr/local/mysql/var6
language   = /usr/local/share/mariadb/japanese
user       = jani

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3 September 2024 MariaDB 11.4