> 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.
> 
> When it came up before, some were saying that the /usr merge violates
> the fhs. I don't remember the specifics of what the claim was at the
> time, (I'm sure someone will point it out if it is still a concern).

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

> 
> 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
> /lib32->usr/lib32
> /lib64->usr/lib64
> /sbin->usr/bin
> /usr/sbin->bin
> 
> Once that is in place in a new baselayout, I think portage's colission
> detection would be able to catch files that had the same names and were
> originally in different paths when building the new stages.

We will have users whose system configurations rely on the FHS complain about 
us breaking boot if we force 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.

This has been an almost annual debate. I do not have much incentive to keep up 
with it. The reason I ever bothered to explain why this is a bad idea for 
Gentoo was that I was concerned for our user base. My systems would not be 
negatively affected and arguing against changes that originated in Solaris is 
awkward for me.

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".

> William
> 
> <usrmerge>


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