/usr on a separate partition

petermiller · n00b Joined: 24 Jul 2004 Posts: 10 Location: Germany

Hello!

I moved my /usr directory to a separate partition and experience
annoying problems since then.

> cat /etc/fstab:

...
/dev/hda7 / ext3 noatime 0 1
/dev/hda1 /mnt/a1 ext3 defaults,noatime 0 2
...

lrwxrwxrwx 1 root root 11 Jun 18 15:53 /usr -> /mnt/a1/usr

The content of usr directory is not directly in the root directory of
the /dev/hda1 partition but instead in a /usr directory on it. I
didn't want to have thousands of files in the root directory and
wanted to use the partition for other directories than usr later as
well.

Now the problems I encounter are:

1) Whenever a shell opens I get this error messages:

-/bin/bash: /usr/bin/whoami: not file or directory
-/bin/bash: [: =: unary operator expected

and when logged in as root I don't have /sbin and /usr/sbin in my
$PATH. I think some script in /etc ('profile' reading 'login.defs'?)
tries to find out if it is root who is logging in to set up the right
$PATH but can't access /usr/bin/whoami as this is a broken link:

lrwxrwxrwx 1 root root 16 Jun 18 15:33 /usr/bin/whoami -> ../../bin/whoami

2) Myriads of broken links in /usr, in fact all relative symbolic
links are broken

So my question is: how can I restore these broken links systematically
and are there other issues to consider when moving /usr on a different
partition?

Thanks for any help

_________________
-- peter

pmjdebruijn · Posted: Sat Jul 24, 2004 10:20 am Post subject:

Well first of all, what you're doing is a very dirty trick! It's also very queer to have a /usr (+data) directory on hda1? Generally that's used a /boot or the likes...

I suggest you get a new improved partitioning scheme :s

But if you insist:
Are you using a hardlink or a softlink? Anyway try them both!

petermiller · n00b Joined: 24 Jul 2004 Posts: 10 Location: Germany

Hello doctor Zoidberg,

It's a symlink. Do you have a good reason to think that switching to a hardlink might solve the problem? I can't repartition the disc, there's also Windows on it and I'm not in the mood to install Gentoo again.

The system seems to work quite OK except for the issues relating to the broken symlinks. Isn't there a tool to correct them?
_________________
-- peter

NeddySeagoon · Posted: Sat Jul 24, 2004 12:09 pm Post subject:

petermiller,

You are breaking the filesystem standard. You are on your own if you do that.

Mount you new /usr in same place as the old one, then everything will just work(tm).

Heres my filesystem

petermiller · n00b Joined: 24 Jul 2004 Posts: 10 Location: Germany

Hi NeddySeagoon

Very nice advice... but useless for me.

This Gentoo installation in question is a clone of a Gentoo installation from my notebook. I tar-ed everything (except /dev and directories like this) on my notebook and untar-ed it on my PC. Since there wasn't enough space on my / partition I had to move /usr to a different partition.

I'm probably looking for a shell script that is at least able to go through /usr tree and list all broken links.

> You are breaking the filesystem standard.

In what exactly am I breaking the standard? You have /usr on a different partition too.
_________________
-- peter

NeddySeagoon · Posted: Sat Jul 24, 2004 12:43 pm Post subject:

petermiller,

You have /usr on /mnt/a1 with a symbolic link from /usr to /mnt/a1. That breaks the standard.

I could have /usr on a sperate drive, say /dev/hdd someplace or even as an NFS mount to somewhere on the other side of the world. It would still just work.

*NIX stye filesyesms navigate their way around one huge tree, the underlying physical structure doesn't matter. When you move things around (and tar is fine provided you preserved permissions and so on) it all works in its new home providing you put the bits back together on the right filesystems. The finishing touch is /etc/fstab, which sticks it all together at power up.

I don't understand why you can't

petermiller · n00b Joined: 24 Jul 2004 Posts: 10 Location: Germany

>I don't understand why you can't
> Code:
> mount /dev/hda1 /usr
>which is what your symbolic link is trying to do.

Because I think this way I would end up with /usr/usr/* unless I can
'mount /dev/hda1/usr /usr'

I didn't want to copy /usr into the directory tree root on /dev/hda1 - I'd like to use /dev/hda1 for other directories than usr later too.

If nothing helps I'll follow your advice and move the contents of usr on /dev/hda1 one directory up (to the /dev/hda1 directory tree root) and 'mount /dev/hda1/ /usr' without the symlink.

Thanks!
_________________
-- peter

NeddySeagoon · Posted: Sat Jul 24, 2004 1:42 pm Post subject:

petermiller,

I understand a little better. When you tarred up /usr, you included the /usr in all the path names so that now /mnt/a1 contains the single directory /usr.
As you say, that would give you /usr/usr if you did my mount suggestion. You cannot do /mnt/dev/hda1/usr /usr which is what you rightly say you need, at least not directly.
However, you can mount things several times. I'll refer you to man mount for the detail. Heres what to do.
Keep your mount /dev/hda1 /mnt/a1, which gets you /mnt/a1/usr, now issue a

Anime_Fan · Posted: Sat Jul 24, 2004 2:15 pm Post subject:

Hmmm

Couldn't he also do this?

NeddySeagoon · Posted: Sat Jul 24, 2004 2:27 pm Post subject:

Anime_Fan,

That would make life a hell of a lot easier but one of the posts suggeted that it was not desired.

When mount --bind is run /usr is still going to be a symlink, (if its mounted at all) otherwise you wouldn't need to run mount --bind in the first place. Whats the problem?
The mount command is in /bin
_________________
Regards,

NeddySeagoon

Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.

petermiller · n00b Joined: 24 Jul 2004 Posts: 10 Location: Germany

NeddySeagoon & Anime_Fan, your suggestions were just what I needed!

Thanks folks!

>Couldn't he also do this?
>
>Code:
>cd /mnt/a1/usr
>mv * ..
>cd ..
>rmdir usr

Yes, I was considering doing this in my previous post but I didn't want to have hundreds of files directly in /mnt/a1/. Mount --rebind is much better for me (hope it can be put into fstab as you say, Anime_Fan).
_________________
-- peter

Anime_Fan · Posted: Sat Jul 24, 2004 2:53 pm Post subject:

NeddySeagoon · Posted: Sat Jul 24, 2004 2:58 pm Post subject:

Anime_Fan,

Mmm, I had at the back of my mind that /mnt/a1 would just be forgotten about. df will report the same free space in two different places in the filesystem, rather than twice the free space.
As Douglas Adams said, its mostly harmless.
_________________
Regards,

NeddySeagoon

Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.