There's almost no testing and validation needed for something like AWS RDS Postgres backups. Occasionally you store an instance and that's it.
Other things like Postgres out-of-disk-space is a 10 min fix on AWS to increment the assigned space. If your VM provider is offering SAN/NAS you may be in luck, otherwise hopefully you have a balast file or some logs you can delete to free enough space to get things running long enough to fix the problem.