We run a couple of database-clusters for our infrastructure:

• Postgres for puppetDB
• Mariadb for anything else

The specific clusters are documented in the sub-pages of this page:

Backups

We run backups in one of two ways, either locally or remotely. Typically one of the database-servers in the cluster sends their backups remotely while the others does it locally.

• Local backups are regularly dumping the content of their databases to "/var/backups/MysqlDump*". Old backups are automaticly deleted to prevent full disks.
• Remote backups are basically the same thing, but pushed to a NFS-share.