On Wednesday, April 6, 2016 6:15:58 AM CEST, Richard Yao wrote:
On Apr 4, 2016, at 9:19 PM, William Hubbs <willi...@gentoo.org> wrote:
All,
I thought that since the usr merge is coming up again, and since I lost
track of the message where it was brought up, I would open a
new thread to discuss it. ...
Here are the violations:
http://refspecs.linuxfoundation.org/FHS_3.0/fhs-3.0.html#binEssentialUserCommandBinaries
http://refspecs.linuxfoundation.org/FHS_3.0/fhs-3.0.html#sbinSystemBinaries
http://refspecs.linuxfoundation.org/FHS_3.0/fhs-3.0.html#libEssentialSharedLibrariesAndKern
well, those are not violations: fhs mandates a certain set of binaries in
those paths; this is still the case with a usr-merged system.
i thought the symlinks would be a problem, but fhs states:
The following directories, or symbolic links to directories, are required in /.
so, really, i dont see any violation there
I don't think creating usr merged stages would be that difficult. I
think it would just be a matter of creating a new version of baselayout
that puts these symlinks in place:
/bin->usr/bin
/lib->usr/lib ...
We will have users whose system configurations rely on the FHS
complain about us breaking boot if we force this.
i dont think anybody is talking about forcing this
I put some thought also in how to nigrate live systems, and I'm not sure
what the best way to do that is. I wrote a script, which would do it in
theory, but I haven't tested because I only have one system and if
it breaks it the only way back would be to reinstall.
The script is attached.
Thoughts on any of this?
This was invented in Solaris and copied by RHEL. The upgrade
path for the /usr merge on those systems is a complete
reinstall. Upgrading from RHEL6 to RHEL7 this Solaris 10 to
Solaris 11 is not supported. The reason being that there are
ways of configuring the system boot process with the original
layout that break if you try using scripts to migrate to the new
one. A USE flag for the /usr merge that is off by default would
allow us to have both worlds without putting any systems at
risk.
that's what i'm actually more worried about: the fact they failed to have a
proper upgrade path doesnt mean it is impossible, just that it is not easy.
only being able to propose usr-merge for new installs makes it useless for
gentoo imho: i, for once, use only 1 gentoo install for the lifetime of my
/ disk...
note that being able to properly migrate is a *requirement* for having it
as a useflag
If others are not willing to be advocates for those users that
would only make themselves known after an a fundamental change
has been made and people are determined to go ahead with this, I
suggest having and testing a plan for backing out the change
should the backlash from users after systems break be more than
people can stomach. This is not the sort of change we should
make without an "exit strategy".
ironing out that kind of strategy is the point of this thread :)
Alexis.
