@kitten as far as I'm concerned, the main benefit is that I can update my primary or whatever, and if I fuck it up, the secondaries still serve a valid zone. likewise, my hosting provider can have downtime as long as my secondaries are with a different host.
like, DNS is one of the things where outages are quite bad. it fucks up availability of every service that isn't DNS, and it adds load to others' infrastructure because failed queries can't be cached (negative responses can, but not of there was no response at all). so very good to try to avoid. I think the latter point of it actually affecting others' infra (resolvers) is maybe the main reason why some TLDs require at least two nameservers?
@kitten Some TLD's require at least two nameservers, but other than that it is up to how much uptime you want. You could ofc use a hidden primary/secondary dns to have multiple nameserver records while still only having to maintain one nameserver yourself.
On an unrelated note, when SERVFAIL eventually has downtime, it's gonna be pretty funny when all my websites and such just fall apart, as well as a whole lot of my friends' websites
