Re: [gentoo-dev] usr merge

[William Hubbs]

On Thu, Apr 07, 2016 at 11:12:13AM +0200, Alexis Ballier wrote:
> On Wednesday, April 6, 2016 11:36:09 PM CEST, Richard Yao wrote:
> > As for those benefits, they do little for {/usr,}/sbin vs
> > {/usr,}/bin, which is where the incompatibilities tend to live.
> > I encountered one of these in powertop the other day (patch
> > pending). The benefits of being able to access things from both
> > places are somewhat exaggerated given that compatibility among
> > systems has long required searching $PATH and likely always
> > will.
>
> PATH is a shell thing; some libc functions like execvp duplicate this
> functionality but that's all; you dont have PATH in shebangs nor in execv.
>
> >> Note, we are not
> >> talking about squashing /usr out of the equasion, but merging /bin,
> >> /sbin and /lib* into their counterparts in /usr and creating symlinks in
> >> the root directory pointing to the counterparts in /usr.
> >
> > While one guy did the reverse (and the reverse ought to be okay
> > for those that want to do that), no one appears to think that
> > adopting the reverse is what is being suggested. Having this
> > sort of clarity on whether forcing this on everyone via
> > baselayout update, just providing the option for those who want
> > it or some combination of the two (e.g. a long transition period
> > in which both are supported) is being discussed would be nice
> > though. This is not a Boolean decision.
>
> I've been under the impression since the beginning of the thread that it is
> what is being proposed: make it possible but support both. We can't force
> usr-merge without battle testing the migration process anyway, which means
> there needs to be such a long transition period.

I do agree that we need a testing period to iron out the migration
process. Like I said, I'm not quite comfortable even with running it
here because I don't know if it will break my system, and once you do
the migration, the only way to undo it is to wipe and re-install. I have
thought about a way to roll back, but I don't see that as very feesable,
so once you migrate to a /usr merged setup, there is no way to undo it.

Also, the usr merge affects linux only; we aren't talking about
messing with *bsd.

After the testing period is over, I'm confused about why we should
support both layouts. With separate usr without initramfs gone, the usr
merge is transparent to end users because of the symbolic links in /, so
there should be no reason to keep supporting both layouts once we are
satisfied with the migration process.

William