So if you put a 3-way cluster in the same building and they lose power together, then what? Is your data toast?
If it's just the write buffer at risk, that's fine. But the chance of overlapping power loss across multiple sites isn't low enough to risk all the existing data.
It's downright stupid if you build a system that loses all existing data when all nodes go down uncleanly, not even simultaneously but just overlapping. What if you just happen to input a shutdown command the wrong way?
I really hope they meant to just say the write buffer gets lost.
Again, I'm not concerned for new writes, I'm concerned for all existing data from the previous months and years.
And getting in this situation only takes one out of a wide outage or a bad push that takes down the cluster. Even if that's stupid, it's a common enough stupid that you should never risk your data on the certainty you won't make that mistake.
You can't protect against everything, but you should definitely protect against unclean shutdown.
Also, garage gives you the possibility to automatically snapshot the metadata, advices on how to do the snapshotting at the filesystem level and to restore that.
How do filesystem level snapshots work if nodes might get corrupted by power loss? Booting from a snapshot looks exactly the same to a node as booting from a power loss event. Are you implying that it does always recover from power loss and you're defending a flaw it doesn't even have?