Note: This is an RHCE 7 exam objective.
Presentation of MariaDB
MariaDB is a binary replacement for MySql, the famous database system.
As the default MariaDB installation uses the /var/lib/mysql directory to store your databases, keep in mind that the partition or logical volume associated with /var needs adequate space.
To install it, apply the following steps:
Install the MariaDB packages:
# yum install -y mariadb mariadb-server
Start and activate at boot the MariaDB service:
# systemctl start mariadb && systemctl enable mariadb
Execute the basic setup:
# mysql_secure_installation /usr/bin/mysql_secure_installation: line 379: find_mysql_client: command not found NOTE: RUNNING ALL PARTS OF THIS SCRIPT IS RECOMMENDED FOR ALL MariaDB SERVERS IN PRODUCTION USE! PLEASE READ EACH STEP CAREFULLY! In order to log into MariaDB to secure it, we'll need the current password for the root user. If you've just installed MariaDB, and you haven't set the root password yet, the password will be blank, so you should just press enter here. Enter current password for root (enter for none):
type enterOK, successfully used password, moving on... Setting the root password ensures that nobody can log into the MariaDB root user without the proper authorisation. Set root password? [Y/n] Y New password: your-passwordRe-enter new password: your-passwordPassword updated successfully! Reloading privilege tables.. ... Success! By default, a MariaDB installation has an anonymous user, allowing anyone to log into MariaDB without having to have a user account created for them. This is intended only for testing, and to make the installation go a bit smoother. You should remove them before moving into a production environment. Remove anonymous users? [Y/n] Y ... Success! Normally, root should only be allowed to connect from 'localhost'. This ensures that someone cannot guess at the root password from the network. Disallow root login remotely? [Y/n] Y ... Success! By default, MariaDB comes with a database named 'test' that anyone can access. This is also intended only for testing, and should be removed before moving into a production environment. Remove test database and access to it? [Y/n] Y - Dropping test database... ... Success! - Removing privileges on test database... ... Success! Reloading the privilege tables will ensure that all changes made so far will take effect immediately. Reload privilege tables now? [Y/n] Y ... Success! Cleaning up... All done! If you've completed all of the above steps, your MariaDB installation should now be secure. Thanks for using MariaDB!
If you need to access the database from a different server, add the MySql service to the firewall configuration and reload it:
# firewall-cmd --permanent --add-service=mysql success # firewall-cmd --reload success
To help you define the initial configuration according to the specifications of your system (memory size, number of CPU, type of activity, etc), you can find useful examples of my.cnf files in the mariadb-server package:
# rpm -ql mariadb-server | grep my- /usr/share/mysql/my-huge.cnf /usr/share/mysql/my-innodb-heavy-4G.cnf /usr/share/mysql/my-large.cnf /usr/share/mysql/my-medium.cnf /usr/share/mysql/my-small.cnf
Start by reading the /usr/share/mysql/my-innodb-heavy-4G.cnf file because it is full of useful comments.
Then, download Major Hayden’s mysqltuner.pl. After running this script, you will get a rough evaluation of your configuration and basic recommentations to improve it.
The innotop package contains a command with the same name that behaves like the top command on MariaDB servers, providing a lot of details about the current activity (cache, locks, replication status, etc). This package is available in the EPEL repository.
Additional information about the transition from MySQL to MariaDB is available on Kolbe’s blog.
Rackspace offers an interesting tutorial about installing and configuring a MySQL/MariaDB server.
Carla Schroder’s blog provides some thought about which type of file system to choose and what are the best parameters to set performance-wise.
A presentation about database performance tuning was given at the 2015 Red hat Summit (the associated slides are there).
The linuxpitstop website provides some tips to improve MariaDB performance.
If you are more interested in Oracle products, Red Hat wrote a document about Deploying Oracle RAC Database 12c on RHEL 7.
You can also watch Andrew Mallett‘s video about Installing MariaDB (6min/2015).
Ramesh Natarajan provides an interesting tutorial on How to Move your MySQL Data Directory to a New Location.
The Digital Ocean website has got a tutorial on How to Change a MariaDB Data Directory to a New Location on CentOS 7.
The askapache website offers a tutorial on how to compile MariaDB with LZ4 compression.