Not sure what the status of this is considering another posting about Wiki's, but ... I'll ask ..
One can have either MySQL *or* MariaDB running on server ... practically the same service using the same ports. If MySQL is running, the config.php file in moodle should have 'mysqli' for the DB driver.
So in Webmin, under System, click Bootup and Shutdown. Scroll down the list to the 'm's'. If it's mysql that running/installed, one will see a line:
| mysqld.service | MySQL Community Server | Yes |
Yes |
The first yes is for "Start at boot" and the second is for "Running now?"
What does your screen say?
If mysqld.service is running then under Servers of Webmin, there should be a MySQL Database Server link and clicking on it should either prompt you for the superuser password OR one should see a 'control panel' that displays at the top the version of MySQL running with databases as well as modules for things like User permissions, Database permissions, Host permissions, etc. Databases should show your moodle database ... whatever you called it.
Moodle runs just fine with either one ... MariaDB or MySQL ... really no compelling reason to not use MySQL. (DB admins might debate that, however)
'spirit of sharing', Ken