On the other hand though, updates on OpenBSD are the most painless updates I have ever done. I am more concerned about it's usage of UFS instead of something more robust for drives.
(IMO it's fine for heavier-write cases, too. It's just especially alright for the common deployment case where it's practically read-only anyway.)
You'll definitely want to have it on a UPS to avoid some potentially long and sometimes manual intervention on fscks after a power failure. And of course, backups for anything important.
I see we have a post-syspatch (6.1 - 2017), post-sysupgrade (6.6 - 2019) OpenBSD user in our midsts. ;D
You are positively a newbie in the OpenBSD world !
Some of us are old enough to remember when OpenBSD updates were a complete pain in the ass in involving downloading shit to /usr/src and compiling it yourself !
And yes, back then I wasn't using OpenBSD.
According to Wikipedia, Debian has had apt since 1998.
My point is OpenBSD didn't have binary updates until well into the 2000's as mentioned above. Initially in 2017 with syspatch and the finally full coverage in 2019 when sysupgrade came along.
As you can see on some old OpenBSD Mailing List posts[1] there was a high degree of resistance to the very idea of binary updates. People even being called trolls when they brought up the subject[2] or being told they "don't understand the philosophy of the system"[3]
I just felt it was an important point of clarification on your original post. Yes, I agree, OpenBSD updates are painless ... now, today. But until very recent history they were far from painless.
[1] https://misc.openbsd.narkive.com/IOf20unK/openbsd-binary-upd... [2] https://marc.info/?l=openbsd-misc&m=117255609026625&w=2 [3] https://marc.info/?l=openbsd-misc&m=117256318700031&w=2
And there was something with ... Postgres ? At some point? Both of course upstream issues that couldn't be helped.
For Debian, I've managed to do in-place upgrades of a few machines from Debian 5 to 10 at the last place I worked.