Plus "written by cperciva and heavily battle tested by Serious Sysadmins" is a feature I couldn't recreate myself - notice that while there was an outage, part of the reason for it taking a while was a conscious choice to take a much longer path to resolution than bringing up the previous server in the name of paranoia. Paranoia about data corruption is a nice thing to have in a backup system and something I'm happily willing to trade-off uptime for.
However: For backups of bulk data then, yes, it's going to be relatively expensive. I wouldn't put e.g. my media backups on tarsnap, but "use tarsnap for your git repositories and other high value data, and something else for the rest" is both perfectly doable and an approach I suspect cperciva himself would endorse.
As Actual Serious Sysadmin that Actually Manages Big Systems for Living that screams more lack of preparation than anything else.
Yes you should be careful but you should also have procedures in place and know the system well enough to trust it. And the fact is that the "boring" architecture of RDS DB instead of that S3 database abomination thing would just start right up if master DB server failed.
It honestly looks like a trap many intelligent people fall into where they turn their cool-but-ulimately-flawed mental excercise into bedrock of the product. I don't want to use baby's-first-database on my production servers (I'm looking at you Lennart Poettering and journald) and I don't want my data/metadata stored on some experimental one.
Without agreeing or disagreeing with those, "I'm not going to trust the filesystem on the existing machine" was the choice I was talking about.
The tarsnap architecture still does more things.
You're welcome to feel that you don't need those things, but that wasn't my point.
I have written about this some time ago if you’re interested: https://www.franzoni.eu/ransomware-resistant-backups/
There's also a service like rsync.net where you can just rsync to the destination and they do the versioning and so on for less than 10th of the cost of tarsnap.
