Re: [gentoo-dev] Opinion against /usr merge

[William Hubbs]

On Tue, Jul 17, 2012 at 05:20:13PM -0400, Richard Yao wrote:
> An often cited benefit of the /usr merge is the ability to put
> everything but /etc on NFS and for that reason, we need to force an
> initramfs on people happily using /usr without it.
 
 This is not quite correct. The initramfs is required because of [1].

> Interestingly, the /usr merge changes made to genkernel permit us to
> mount /etc from a genkernel-built initramfs by putting /etc on a
> separate mount point in fstab and then doing `echo /etc >>
> /etc/initramfs.mounts`.
 
That doesn't negate putting /usr on nfs and making it possible for
different hosts to share it.

> Some people claim that the current approach is somehow broken by citing
> Bluetooth keyboards. However, what makes that work is adopting an
> initramfs and that does *not* require moving files into /usr. If people
> do not want an initramfs, they can simply not have a separate /usr. The
> /usr merge gives nothing to people using bluetooth while the /usr merge
> will break systems of non-bluetooth users.

I don't see what bluetooth has to do with anything other than with the
'separate usr is broken' document which is a separate issue.

> I have been told that moving everything into /usr would be easy for us
> because Arch Linux did it and they are a rolling distribution too. Arch
> Linux does all-or-nothing upgrades. They do not offer the ability for
> their users to choose to use older versions of software and we will not
> be able to move everything into /usr without breaking existing systems
> that boot without issues now.
 
 This issue is not completely flushed out with the upstream folks for
 udev yet, and  either way, it will be addressed in our version of udev.

> I have also been told that the /usr merge is necessary because upstream
> will force it on us. Interestingly, most of @system on Gentoo Linux is
> GNU software, which would need to stop supporting things in / in order
> for that to happen. As far ass I know, systemd does not work on GNU HURD
> and it would be incapable of functioning if the GNU project made this
> change. Hell will freeze long before that happens.
 
This is basically not relevant since we do not support HURD.

> The only thing that might require a merge is systemd and it is not in
> @system. If we offered users the ability to choose rc systems, we would
> still be supporting baselayout-1's rc system. If we start now, we should
> bring that back.
 
 We offer several rc systems in the tree, but I don't know how up to
 date they are. Either way, bringing back bl1 is not a relevant
 argument, because it is not compatible with OpenRC.

> With that said, there is a great deal of FUD being spread by the systemd
> developers and I see no reason for us to accept it. We would be breaking
> users' systems for no gain other than to make the systemd developers
> happy. Their refusal to permit udev to be built separately from systemd
> demonstrated complete disdain for Gentoo Linux. Why should we let them
> dictate how we design our distribution at our users' expense?

I think we can do the /usr merge in a way that won't break systems; I am
looking into that possibility. I am not interested in breaking systems.

> Lastly, don't tell me to read systemd's case for why we should break
> people's systems. I have read it and I find it flawed. There is
> absolutely no need for us to make this change.
 
Without elaboration on why you find their case flawed, this sounds
like the typical, "if it isn't broke, don't fix it" argument.
While that has merrit, if there are advantages to doing
 something, like I think there would be to doing the /usr merge, it may
 be worth the transition, especially if we can make it as smooth as
 possible.

William