[systemd-devel] Antw: [EXT] Re: Dropping split-usr/unmerged-usr support

[Ulrich Windl]

>>> Mike Gilbert <floppym at gentoo.org> schrieb am 06.04.2022 um 17:24 in Nachricht
<CAJ0EP43Y7s7WZDF1KHdtj2uQdokAb4EqhsppBQT9W1sP5oBbcQ at mail.gmail.com>:
> On Tue, Apr 5, 2022 at 4:07 PM Luca Boccassi <luca.boccassi at gmail.com> wrote:
>>
>> Hi,
>>
>> As part of our spring cleaning effort, we are considering when to drop
>> support for split/unmerged-usr filesystem layouts.
>>
>> A build-time warning was added last year:
>>
>> 
> https://github.com/systemd/systemd/commit/9afd5e7b975e8051c011ff9c07c95e80bd9 
> 54469
>>
>> We are now adding a runtime taint as well.
>>
>> Which distributions are left running with systemd on a split/unmerged-
>> usr system?
> 
> Gentoo still supports having /{bin,sbin,lib} and /usr/{bin,sbin,lib}
> as separate directories. We do not support officially booting without
> /usr mounted (via initramfs), but some users do it anyway.
> 
> We are not likely to require merging of / and /usr for the foreseeable
> future. We are a "rolling release" distro and basically never require
> our users to re-install, which makes large file system migrations
> difficult. Also, many of our users would resist any attempt to force
> merged-/usr on them.

Well, many years ago HP-UX (I think it was around major version 9 or 10) managed to migrate from /bin to /sbin and /usr/sbin (also from /usres/ to /home) without reinstallation.
I always felt what systemd is demanding is a step back.

> 
> I think it would be ok if systemd drops support for installing itself
> in /lib/systemd; we would just move everything under /usr/lib/systemd,
> and possibly set up some symlinks in /lib/systemd for the transition.
> 
> We will still need to keep /bin and /sbin in PATH, and we can't assume
> that all binaries reside in /usr/bin.

What speaks for /sbin and /usr/sbin IMHO is the fact that the typical user did not have them in the PATH, because those were mostly management commands a normal user does not need.
Now we have a "huge pot" with everything in /usr/bin.

Regards,
Ulrich