MariaDB

This component sets up a managed instance of the MariaDB database server.

Supported versions

There’s a role for each supported version, currently:

  • mariadb114: MariaDB 11.4 (LTS)

  • mariadb118: MariaDB 11.8 (LTS)

We recommend the use of mariadb118, as this is the most up to date LTS release. All of versions marked with EOL don’t receive security updates and are only included to allow the upgrade of existing machines to this platform version.

Configuration

MariaDB works out-of-the box without configuration.

The mysql user is authenticated by socket auth with the mysql system users.

Custom config files in /etc/local/mysql are included in the main mysql configuration file on the next system build. Add a local.cnf (or any other *.cnf) file there, and run sudo fc-manage switch to activate the new configuration.

Note

Changes to *.cnf files in this directory will restart MariaDB to activate the new configuration.

Interaction

Service users can use sudo -iu mysql to access the MySQL mysql account to perform administrative commands as well as log files in /var/log/mysql. To connect to the local MariaDB server, run mariadb as mysql user:

sudo -u mysql mariadb

The MariaDB server can be accessed from other machines in the same resource group on the default port 3306.

Slow Log

SQL statements that take longer than 100 milliseconds to run, are logged to /var/log/mysql/mysql.slow. The log file is rotated when file size is greater than 2GB or at least weekly.

The default of 100 milliseconds for slow queries can be changed with a global option: SET GLOBAL long_query_time=1.5; where the value is the time in seconds.

Backup

For backup tasks the xtrabackup command is provided, along with sudo permission for executing xtrabackup from the service user as root.

Monitoring

The default monitoring setup checks that the MariaDB server process is running and that it responds to connection attempts to the standard MariaDB port (3306).

Populating with Initial Data

For populating the database with data or executing other custom SQL commands at first startup, the NixOS option services.percona.initialScript can be set to a file containing such SQL commands.

Caution

This is mainly useful for Development Host deployments, as the script will only be executed at first startup and is ignored afterwards.

Enabling a Percona role first and only setting an initial script later won’t have any effect anymore.