I have a 56 TB local Unraid NAS that is parity protected against single drive failure, and while I think a single drive failing and being parity recovered covers data loss 95% of the time, I’m always concerned about two drives failing or a site-/system-wide disaster that takes out the whole NAS.
For other larger local hosters who are smarter and more prepared, what do you do? Do you sync it off site? How do you deal with cost and bandwidth needs if so? What other backup strategies do you use?
(Sorry if this standard scenario has been discussed - searching didn’t turn up anything.)


Honestly, I’d buy 6 external 20tb drives and make 2 copies of your data on it (3 drives each) and then leave them somewhere-safe-but-not-at-home. If you have friends or family able to store them, that’d do, but also a safety deposit box is good.
If you want to make frequent updates to your backups, you could patch them into a Raspberry Pi and put it on Tailscale, then just rsync changes every regularly. Of course means that wherever youre storing the backup needs room for such a setup.
I often wonder why there isn’t a sort of collective backup sharing thing going on amongst self hosters. A sort of “I’ll host your backups if you host mine” sort of thing. Better than paying a cloud provider at any rate.
That NAS software company Linus (of Linus Tech Tips) funded has a feature for this planned I think.
An open-source standalone implementation would be dope as hell. Sure, it’d mean you’d need to double your NAS capacity (as you’d have to provide enough storage as you use), but that’s way easier than building a second NAS and storing/maintaining it somewhere else or constantly paying for and managing a cloud backup.