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Our current backup strategy is directly copying /srv/mariadb to Bacula. However, that is guaranteed to provide corruption, since no table locks are acquired during the backup. On top of that, retrieving specific databases or tables is a pain.
See https://wikitech.wikimedia.org/wiki/MariaDB/Backups, and https://wikitech.wikimedia.org/wiki/MariaDB/Backups#Snapshoting_and_disaster_recovery in particular. While we can't compare our wiki sizes to Wikimedia's, their backups are generated using commonly used tools: mariabackup (which we're already using for creating replicas) and mydumper (alternative for mysqldump).