MariaDB is an open-source relational database management system that originated as a MySQL fork. Joomla can use MariaDB to store content, accounts and settings when its version requirements are met.
MariaDB and MySQL
Both systems use SQL and share many interfaces. Their releases, features, configuration and behaviour develop separately, however. Similar version numbers do not imply identical capabilities or complete interchangeability.
Using MariaDB with Joomla
For Joomla, check the supported MariaDB version, PHP driver, character set, collation and extension requirements. A successful connection does not prove that every query and update operation is compatible.
Before moving Joomla between database systems, back up the database and files, test recovery on a separate copy and check the site. Pay attention to search, sorting, saving content and installing updates.
Maintenance considerations
A database, a DBMS user and the server service are separate objects. Restarting a service does not correct permissions or a faulty query. Diagnosis should consider the exact server version, logs and actual workload.
Conclusion
MariaDB provides Joomla with relational storage. Evaluate compatibility through requirements and testing of the actual site.