Installing MariaDB alongside MySQL
MariaDB is a drop in place replacement for MySQL, but you can also install it alongside MySQL. (This can be useful, for example, if you want to migrate databases/applications one by one.)
Here are the steps to install MariaDB near an existing MySQL installation.
- Download the compiled binary tar.gz that contains the latest version (mariadb-5.5.24-linux-x86_64.tar.gz - as of writing this article) and extract the files in a directory of your choice. I will assume for this article that the directory was /opt.
[root@mariadb-near-mysql ~]# cat /etc/issue CentOS release 6.2 (Final) [root@mariadb-near-mysql ~]# rpm -qa mysql* mysql-5.1.61-1.el6_2.1.x86_64 mysql-libs-5.1.61-1.el6_2.1.x86_64 mysql-server-5.1.61-1.el6_2.1.x86_64 [root@mariadb-near-mysql ~]# ps axf | grep mysqld 2072 pts/0 S+ 0:00 \_ grep mysqld 1867 ? S 0:01 /bin/sh /usr/bin/mysqld_safe --datadir=/var/lib/mysql --socket=/var/lib/mysql/mysql.sock ... 1974 ? Sl 0:06 \_ /usr/libexec/mysqld --basedir=/usr --datadir=/var/lib/mysql --user=mysql ...
- Create data directory and symlinks as below:
[root@mariadb-near-mysql opt]# mkdir mariadb-data [root@mariadb-near-mysql opt]# ln -s mariadb-5.5.24-linux-x86_64 mariadb [root@mariadb-near-mysql opt]# ls -al total 20 drwxr-xr-x. 5 root root 4096 2012-06-06 07:27 . dr-xr-xr-x. 23 root root 4096 2012-06-06 06:38 .. lrwxrwxrwx. 1 root root 27 2012-06-06 07:27 mariadb -> mariadb-5.5.24-linux-x86_64 drwxr-xr-x. 13 root root 4096 2012-06-06 07:07 mariadb-5.5.24-linux-x86_64 drwxr-xr-x. 2 root root 4096 2012-06-06 07:26 mariadb-data
- Create group mariadb and user mariadb and set correct ownerships:
[root@mariadb-near-mysql opt]# groupadd --system mariadb [root@mariadb-near-mysql opt]# useradd -c "MariaDB Server" -d /opt/mariadb -g mariadb --system mariadb [root@mariadb-near-mysql opt]# chown -R mariadb:mariadb mariadb-5.5.24-linux-x86_64/ [root@mariadb-near-mysql opt]# chown -R mariadb:mariadb mariadb-data/
- Create a new my.cnf in /opt/mariadb from support files:
[root@mariadb-near-mysql opt]# cp mariadb/support-files/my-medium.cnf mariadb-data/my.cnf [root@mariadb-near-mysql opt]# chown mariadb:mariadb mariadb-data/my.cnf
- Edit the file /opt/mariadb-data/my.cnf and add custom paths, socket, port, user and the most important of all: data directory and base directory. Finally the file should have at least the following:
[client] port = 3307 socket = /opt/mariadb-data/mariadb.sock [mysqld] datadir = /opt/mariadb-data basedir = /opt/mariadb port = 3307 socket = /opt/mariadb-data/mariadb.sock user = mariadb
- Copy the init.d script from support files in the right location:
[root@mariadb-near-mysql opt]# cp mariadb/support-files/mysql.server /etc/init.d/mariadb [root@mariadb-near-mysql opt]# chmod +x /etc/init.d/mariadb
- Edit /etc/init.d/mariadb replacing mysql with mariadb as below:
- # Provides: mysql + # Provides: mariadb - basedir= + basedir=/opt/mariadb - datadir= + datadir=/opt/mariadb-data - lock_file_path="$lockdir/mysql" + lock_file_path="$lockdir/mariadb"
The most tricky part will be the last change in this file. You need to tell mariadb to use only one cnf file. In the start section after $bindir/mysqld_safe add --defaults-file=/opt/mariadb-data/my.cnf. Finally the lines should look like:
# Give extra arguments to mysqld with the my.cnf file. This script # may be overwritten at next upgrade. $bindir/mysqld_safe --defaults-file=/opt/mariadb-data/my.cnf --datadir="$datadir" --pid-file="$mysqld_pid_file_path" $other_args >/dev/null 2>&1 &
- Run mysql_install_db by explicitly giving it the my.cnf file as argument:
[root@mariadb-near-mysql opt]# cd mariadb [root@mariadb-near-mysql mariadb]# scripts/mysql_install_db --defaults-file=/opt/mariadb-data/my.cnf
- Now you can start MariaDB by
[root@mariadb-near-mysql opt]# /etc/init.d/mariadb start Starting MySQL... [ OK ]
- Make MariaDB start at system start:
[root@mariadb-near-mysql opt]# cd /etc/init.d [root@mariadb-near-mysql init.d]# chkconfig --add mariadb [root@mariadb-near-mysql init.d]# chkconfig --levels 3 mariadb on
- Finally test that you have both instances running:
[root@mariadb-near-mysql ~]# mysql -e "SELECT VERSION();" +-----------+ | VERSION() | +-----------+ | 5.1.61 | +-----------+ [root@mariadb-near-mysql ~]# mysql -e "SELECT VERSION();" --socket=/opt/mariadb-data/mariadb.sock +----------------+ | VERSION() | +----------------+ | 5.5.24-MariaDB | +----------------+
What about MariaDB Upgrades ?
By having the mariadb.socket, my.cnf file and databases in /opt/mariadb-data if you want to upgrade the MariaDB version you will will only need to: - extract the new version from the archive in /opt near the current version - stop MariaDB - change the symlink mariadb to point to the new directory - start MariaDB - run upgrade script... but remember you will need to provide the socket option --socket=/opt/mariadb-data/mariadb.sock