Database From Online Manual
SMF uses either a MySQL, PostgreSQL, or SQLite database to store all of the data on the forum.
In SMF 1.1, the only supported database scheme is MySQL.
PostgreSQL and SQLite support with SMF was introduced in SMF 2.0.
Your database is where all of your posts, topics, members, settings and much more are stored. It is a wise idea to backup your forum database often. You should never back it up through the SMF admin panel > Forum Maintenance > Backup Database.