Very hard lesson, indeed. Mark gives us a very harsh reality to know and stresses the importance of taking a working backup of GP Data.
Yeah, it is not just taking a backup. It is also imperative to confirm the backup set, that we have taken, actually works. Read his article: Backup, Backup, Backup.
Please remember: Taking Backup Set of GP Data is very very important. Even more important is to test it whether it is safe and working.