Are you OP though?

Neither actually lol.

Embedded Linux style squashFS + UBI forever

I haven't tried any yet, but my understanding is that recently there's been a trend of immutable Linux distros, where the root filesystem is immutable (read-only). Instead of directly changing stuff in /etc, installing apps, etc, you instead update some sort of config that says exactly how to set up the system, and rerun a script that rebuilds the root.

System updates are atomic - either the whole update is completed, or the whole update is rolled back. If the system breaks, you can revert back to an old config file and restore it to exactly the same state as it was before.

It's still not very common - the majority of Linux systems aren't doing this.

You use reproducible, read only rootfs (essentially what a "live" distro is, to some extent) because it's 1, reproducible, so you're not stuck when the system dies for some weird reason 2, it's read only meaning nothing will modify it. This gives you a base that is stable, easily reproduced on any host, and isn't up to the whims of what packages you installed and such.

NixOS is a good candidate for this approach but you can literally turn any distro into such a base. Though it's preferred to use one dedicated to such endeavours.

Nobody said anything about bulk mounting anything though? I said mount your data partitions, because presumably you'd have multiple disks holding your data thus multiple partitions...

And the fact you've been working with Linux for 20+ years and have no fucking clue about why someone would want their rootfs RO or RW makes me seriously worried about the very statement that you worked with Linux for 20 years without an understanding of such a basic OS function.

I start sshd Yes do passwd and connect from my main machine Yes yes Then I just quickly format disks, and pacstrap system Yeeesssss by copy-pasting commands from my blog Bah. Why not put them in an Ansible playbook? Save yourself the extra blog traffic!

Sadly you sentence is all i get, when i try to research the how. Any example config, want either the drive big enough for all data or both servers conected.

Probably have to do something hacky.