View the original community article here
Last tested: Oct 24, 2018
This means that the instance is on a MySQL internal db, and the product doesn't do S3 backups for MySQL.
If you are Looker-hosted, we automatically create backups using a process outside of the Looker app, so you don't need to worry about this message.
If you host your own instance, you'll need to create your own backups.