From: "Theo de Raadt" <deraadt@openbsd.org>
Subject: Re: install.sub: don't require bsd(.sp) on multi-core machine
To: "Alexander A. Klimov" <a@kli.mov>
Cc: tech@openbsd.org
Date: Wed, 01 May 2024 13:05:53 -0600

Alexander A. Klimov <a@kli.mov> wrote:

> On 01.05.24 18:03, Klemens Nanni wrote:
> > On Wed, May 01, 2024 at 05:10:55PM GMT, Alexander A. Klimov wrote:
> >> SANESETS= specifies only the absolutely necessary sets.
> >> And "bsd" isn't necessary on a multi-core machine,
> >> as it gets replaced with bsd.mp anyway.
> > No, it is renamed into /bsd.sp and needed on MP systems.
> 
> Oh, I have no doubt.
> Every component is there because it's needed for something.
> comp${VERSION}.tgz is needed for compiling e.g. the system itself,
> man${VERSION}.tgz for looking up the latter process...
> But, as my experiment showed, a MP system consisting only of
> bsd.mp and base${VERSION}.tgz boots and operates perfectly.
> Hence, /bsd.sp is (maybe needed as fallback
> in case of a MP bug, but) not *absolutely necessary*.
> 
> But ok, I guess I'll have to answer the "Are you *SURE*"
> question via /auto_upgrade.conf before rebooting...

It has nothing to do with the system running after it is installed.

This is how the installer works.

If you create a sets-directory and intentionally remove that file,
that's on you.