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Old 10-10-2012, 09:39 AM
Serge
 
Default UsrMove continued

2012/10/9 Jochen Schmitt wrote:

> I want to disagree with your suggestion. /root is the home directory of
> the superuser and should not be placed on a network device in opposite
> of the home directories of the ordinary users. The user root should be
> able to logon without a network connection to do any rescue work on
> the system.

This argument would work for original UsrMove feature. But it's already
done. Right now user `root` cannot login without /usr being mounted,
because it needs at least bash, which is now /usr/bin/bash. Moving /root
to /usr is just consistent continuation of implemented UsrMove.

> I want to consider, that /etc should be mounted on a writeable partition
> in opposite of /usr to allow changes without remounting.

Probably you're right, but I can't think of any real-world examples where
it would be needed. Can you name some?

My line of reasoning was: if you're managing a set of machines with shared
/usr you always want /etc to be shared too. It's a pain for admin to
install/update some software and then run across all the machines to
set up new /etc files everywhere. And as long as /etc is also shared
among multiple machines it should be read-only as well as /usr. This is
needed at least as a security measure, so you could be sure that some
bug on one machine won't break everything else.

> your test case didn't hit your suggestion of remove the /etc
> directory.

It did. Check the following line closely:
# mv -f /root /etc /usr/; ln -s usr/root usr/etc /

It actually does not hit the /tmp case (mount-bind is used instead of
symlink). But that's solely because of systemd becoming extremely
unhappy when /tmp is a symlink.

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Old 10-10-2012, 10:11 AM
Serge
 
Default UsrMove continued

2012/10/9 tim.lauridsen wrote:

>> So you make your system incompatible with every other Linux distro out
>> there, and with all existing documentation, but to what end? Tidyness?

Tidyness, simplicity, new features... Incompatible with older, but
compatible with newer distros. That's close to what Solaris does on
its livecd and really close to what Android does on mobile phones.

Turning /lib into /usr/lib was also incompatible with every other Linux
distro, nevertheless it's already done.

> +1 to Richard, I really don't see the purpose, why does it matter that
> number of dirs in /.

I don't know why, but some people actually like when there're fewer
subdirectories in a directory.

> Lot of apps will break if you move /proc or /dev

Sure. And many apps would break if you move /bin to /usr/bin. But still,
you did that?

> and if you replace them
> with symlink in the next 10 years you still have the same number of dirs
> under /, you have even more because you have added some new ones.

That's a compatibility tradeoff. But an "eyecandy" kernel module can hide
those symlinks, so user would see a nice simple layout right now, and not
in 10 years.

> I can understand you want to merge dirs there have the same function /bin ->
> /usr/bin, but this has no benefits at all.

Quite the contrary. If you compare it with the original UsrMove page you
will see that it had same reasons, same "Benefits" and "User Experience",
but no final goal. Original UsrMove was looking like "separate /usr is
partially broken, let's break it completely". It officially declared
that we don't know what files should be put to /bin or /usr/bin, but
it brought no new features.

While this one (besides creating even more "Simpler and cleaner file
system layout") has a goal: making explicit root filesystem optional
(i.e. so small and simple that it could be replaced with initramfs).
Which gives lots of new features, like simple diskless NFS stations,
multiple distros on same partition, easier lightweight containers...

I could understand if arguments against it were suggested before UsrMove
implementation. But it's already there. There're already symlinks to
/bin, /lib, /sbin. Root user already cannot login without /usr being
mounted. And similar selinux issues were already taken care of. Most
of the work is already done. It's not a new suggestion, it's the same
UsrMove, but now it can bring some new features.

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Old 10-10-2012, 10:24 AM
Matěj Cepl
 
Default UsrMove continued

On Wed, 10 Oct 2012 13:11:12 +0300, Serge wrote:
> Turning /lib into /usr/lib was also incompatible with every other Linux
> distro, nevertheless it's already done.

The fact that we've made one useless and harmful mistake doesn't mean
that we should repeat it all the time.

Matěj

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Old 10-10-2012, 10:51 AM
"Richard W.M. Jones"
 
Default UsrMove continued

On Wed, Oct 10, 2012 at 10:24:54AM +0000, Matěj Cepl wrote:
> On Wed, 10 Oct 2012 13:11:12 +0300, Serge wrote:
> > Turning /lib into /usr/lib was also incompatible with every other Linux
> > distro, nevertheless it's already done.
>
> The fact that we've made one useless and harmful mistake doesn't mean
> that we should repeat it all the time.

+1. Only this week and last I had to deal with two small bugs caused
by UsrMove. It's a never-ending source of issues, and needlessly
incompatible with Debian.

Rich.

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Old 10-10-2012, 12:25 PM
David Howells
 
Default UsrMove continued

Serge <sergemdev@gmail.com> wrote:

> > Lot of apps will break if you move /proc or /dev
>
> Sure. And many apps would break if you move /bin to /usr/bin. But still,
> you did that?

The contents of /dev vary depending on what hardware the computer has
available - which may change in real time - so it cannot be shared, so why
move it?

You would _have_ to have symlinks at /dev and /proc - so moving these gains
you nothing. The dirents would still be present on the rootfs - so you'd've
made things less efficient by virtue of mounting these elsewhere and putting
symlinks in. Don't forget also that symlinks are a limited resource in any
particular pathwalk (though I suspect that wouldn't actually be a problem).

> ... But an "eyecandy" kernel module can hide
> those symlinks, so user would see a nice simple layout right now, and not
> in 10 years.

Ugh. Don't go there. Really don't. That's for userspace to deal with - just
like hiding files whose name begins with a ".".

> While this one (besides creating even more "Simpler and cleaner file
> system layout") has a goal: making explicit root filesystem optional
> (i.e. so small and simple that it could be replaced with initramfs).
> Which gives lots of new features, like simple diskless NFS stations,
> multiple distros on same partition, easier lightweight containers...

Which does not prevent you from leaving /dev and /proc where they are.

Actually, the UsrMove has mucked up at least one way of doing things: we
have/had RHEL customer(s) who kept /usr on AFS and were able to boot just
using the stuff in /bin and /sbin. This is no longer a viable option with
Fedora, and presumably RHEL-7.

David
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Old 10-10-2012, 01:04 PM
Michal Schmidt
 
Default UsrMove continued

Dne 10.10.2012 14:25, David Howells napsal(a):

Actually, the UsrMove has mucked up at least one way of doing things: we
have/had RHEL customer(s) who kept /usr on AFS and were able to boot just
using the stuff in /bin and /sbin. This is no longer a viable option with
Fedora, and presumably RHEL-7.


The initramfs should contain everything necessary to mount / and /usr.
Isn't there a dracut module for AFS support? If not, it should be added.
Has a bug been reported?


Michal

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Old 10-10-2012, 01:45 PM
Seth Vidal
 
Default UsrMove continued

On Wed, 10 Oct 2012, Matěj Cepl wrote:


On Wed, 10 Oct 2012 13:11:12 +0300, Serge wrote:

Turning /lib into /usr/lib was also incompatible with every other Linux
distro, nevertheless it's already done.


The fact that we've made one useless and harmful mistake doesn't mean
that we should repeat it all the time.



I cannot agree enough. Just b/c we've blundered down a bad route doesn't
mean you cannot turn back.


Instead of chiseling our way back, let's just revert and go.

Not every decision a distribution makes is a good one, lets not get caught
up believing that we cannot make mistakes.


UsrMove was a mistake. End of discussion. Let's go back.

-sv
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Old 10-10-2012, 01:50 PM
Ben Rosser
 
Default UsrMove continued

On Wed, Oct 10, 2012 at 9:45 AM, Seth Vidal <skvidal@fedoraproject.org> wrote:



I cannot agree enough. Just b/c we've blundered down a bad route doesn't mean you cannot turn back.



Instead of chiseling our way back, let's just revert and go.



Not every decision a distribution makes is a good one, lets not get caught up believing that we cannot make mistakes.



UsrMove was a mistake. End of discussion. Let's go back.


However, whether you believe this or not, UsrMove was at least an attempt to solve an actual potential problem- perceived redundancy in /bin and /lib and /usr/bin and /usr/lib.

I still don't see what problem this proposal would solve. To me it feels like a solution without a problem solely for the sake of tidiness in /.
Ben*
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Old 10-10-2012, 02:52 PM
Chris Adams
 
Default UsrMove continued

Once upon a time, Seth Vidal <skvidal@fedoraproject.org> said:
> Not every decision a distribution makes is a good one, lets not get caught
> up believing that we cannot make mistakes.
>
> UsrMove was a mistake. End of discussion. Let's go back.

I agree. The additional churn would be another one-time pain, but then
the Band-Aid™ would be ripped off and we'd be done.
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Old 10-10-2012, 03:12 PM
David Tardon
 
Default UsrMove continued

On Wed, Oct 10, 2012 at 01:11:12PM +0300, Serge wrote:
> 2012/10/9 tim.lauridsen wrote:
>
> > +1 to Richard, I really don't see the purpose, why does it matter that
> > number of dirs in /.
>
> I don't know why, but some people actually like when there're fewer
> subdirectories in a directory.

Then I suggest that you start with /usr/share/doc.

Also, define "fewer". Is 16 too much? (apparently yes) What about 8? 4?
2? (o, the good old binary tree...) Btw, why is this a "problem" with
directories and not with files too? UsrMove _added_ lots of files to
/usr/bin and /usr/sbin, yet you seem to approve of it...

D.
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