IMHO:
- Yes to backups! You should be taking backups of your databases regularly, and SQL formats are best because they can be loaded into a newer version of MySQL/MariaDB. Here’s an old post on this: Best practice for backup database and all content - #2 by jeff. There may be a more modern way to do this.
- Ubuntu and Debian upgrades are usually pretty safe when they hit production - there are always notes to look at, and MySQL/MariaDB always need a check afterwards. I run the upgrades early on test servers, and about a month after release dates in production. I am already running the next version on my development boxes, which is Debian pre-release Alpha3 aka bullseye, expected out this June.
- Once you have issued your ALTER SCHEMA you have made the change permanent so you won’t need to do that next time.
The only additional thing is to run mysqlcheck -o from time to time - maybe every quarter, when there are no updates being performed, as part of your database health maintenance.
