Gentoo Archives: gentoo-user

From: Alan Mackenzie <acm@×××.de>
To: gentoo-user@l.g.o
Subject: Re: [gentoo-user] Re: After /usr conflation: why not copy booting software to /sbin rather than initramfs?
Date: Wed, 28 Mar 2012 14:04:41
Message-Id: 20120328140132.GA3546@acm.acm
In Reply to: Re: [gentoo-user] Re: After /usr conflation: why not copy booting software to /sbin rather than initramfs? by Alan McKinnon
On Wed, Mar 28, 2012 at 12:55:20AM +0200, Alan McKinnon wrote:
> > On Tue, Mar 27, 2012 at 11:48:19PM +0200, Alan McKinnon wrote: > > > On Tue, 27 Mar 2012 21:24:22 +0000 > > > Alan Mackenzie <acm@×××.de> wrote:
> > > > That is precisely what the question was NOT about. The idea was > > > > to copy (not move) booting software to /sbin instead of an > > > > initramfs - the exact same programs, modulo noise - to have the > > > > SW in /sbin necessary to mount /usr.
> > > Two words:
> > > shared libraries
> > > Copying binaries is not enough. You have to find and copy every > > > shared library those binaries use. Plus all the data and other > > > files they might need.
> > > This is non-trivial.
> > <silently screams>. It's equally non-trivial for initramfs, yet > > nobody seems to be raising this objection for that.
> > Why is nobody else on this thread willing to take up its main point, > > the exact equivalence between the known, ugly, initramfs solution and > > the as yet half-baked idea of putting the same binaries into /sbin?
> Read my other mail and pay attention to the difference between > transient and persistent.
In my proposed solution, the executables in /sbin would only exist until /usr had been mounted and the runtime PATH set up. After the unification of /usr, /sbin won't even exist (apart from in schemes like mine).
> initramfs is an elegant engineering solution (albeit over-engineered > for our specific case of being Gentoo users).
Maybe, maybe not. It couples the various bits of booting more tighly together. I look at Allan Gottlieb's bug "WARNING latest lvm2 breaks systems with older udev", and note that he recovered, essentially, by mounting non-/ partitions by hand and going back to an old lvm2 version. I had a similar problem when I was first trying out Walter's mdev solution, which I also recovered by mounting by hand. I look forward with foreboding to the time when such recovery will not be possible. Only a legacy Gentoo system or a recovery CD will help then. I think it highly probable that "can't boot" bugs will continue to happen occasionally. I'd like to carry on having a bootable skeleton system for when this happens.
> Your questions are about an extremely ill-advised action that has no > sound basis. It copies stuff around to make one very specific thing > work but with zero consideration for what it will do to everything > else. That is bad, bad engineering.
I don't think that's a fair summary.
> If you want all this stuff in /, then do it correctly and modify the > ebuilds to put the originals there (and troubleshoot the fallout from > other faulty hard-coded stuffs). This is a lot of work, but it is sound.
I doubt that would work, for the reasons you give. I feel I've been needlessly slammed, all for articulating an interesting idea.
> -- > Alan McKinnnon > alan.mckinnon@×××××.com
-- Alan Mackenzie (Nuremberg, Germany).

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