Hi,

On Mon, 2026-06-29 at 12:33 -0500, o1bigtenor via Dng wrote:
> On Mon, Jun 29, 2026 at 11:37 AM Lorenz via Dng <dng@???>
> wrote:
> >
> > Hi,
> >
> > On Mon, Jun 29, 2026 at 4:36 PM Hendrik Boom
> > <hendrik@???> wrote:
> > >
> > > what happens if during usrmerge you run out of space on /usr ?
> > > does usrmerge back out gracefully, leaving the system intact?
> >
> > I don't know for sure, maybe it has some sefaguards. If you can
> > readperl, usrmerge is a perl script
> >
> > >
> > > is there a good way of estimating how much space will be needed
> >
> > roughly, the sum of the following
> > # du -hs /bin
> > # du -hs /sbin
> > # du -hs /lib
> > # du -hs /lib64
> >  what it does, I think, is to copy everything in the above dirs
> > into
> > their /usr counterparts,
> > so /bin into /usr/bin and so on, and then it replaces /bin, /sbin
> > and
> > so on with symlinks to
> > their user counterparts. It's not an atomic move, if you are
> > wondering.
> > you might need twice the above space because it may copy stuff in
> > /bin /sbin/ /lib /lib64 to a backup before removing it (not sure).
> > It's not a large amount of space, usually.
> >
> > > so i can repartition first if necessary?
> >
> > this question rings a bell: I'm not sure that's your case but I
> > think the only thing that is not supported in a usrmerged system is
> > to have a /usr partition separate from root.
>
> Please - - - - could you check if this is true?
>
> If it is this is why I cannot boot what I call my trial box.
>
> I've been running these separate partitions
> /
> /boot
> /usr
> /usr/local
> swap
> /var
> /home
>
> for some almost 20 years.
> Have had a lot of issues keeping /usr large enough (think this box is
> at
> 25 GB).
>From how you describe your system I wouldn't be surprised if you might
be falling foul of the copy space issue but also having your systems
files now in /usr on a separate partition so not being accessible on
boot.

I suspect usrmerge is not detecting your non-compliant configuration
and breaking you system. Apt is similarly unhelpful in not telling you
about temporary space required when upgrading until you have actually
exhausted it.

I found this reference on Mastodon as to why we got into the current
historical existence of /bin, /sbin, /usr/bin, usr/sbin. 
https://lists.busybox.net/pipermail/busybox/2010-December/074114.html
TL;DR there's no logical reason these days to split where we put our
binaries.

I think the same may largely apply to not putting everything but /home
and /swap on the same root partition. By using LLM2 you can also
spread your partition(s) over more than one disk, as well as to
dynamically allocate more space to them as required.

--
Marjorie