"df" output not showing mounted NFS volumes

ferg

Hi all,

I have a very confusing issue. On two Gentoo systems (both kept reasonably up to date, but only recently rebooted) I am having issues with some mounted NFS volumes (the same ones on both machines).

If I run "mount -l -t nfs" to list all mounted volumes of type "nfs" I see them.

ce110ut · Apprentice Joined: 27 Sep 2002 Posts: 200

Hello ferg,

Is /mnt/motion mounted for sure? That may be why it's not showing up in df.

ferg · Posted: Tue Mar 12, 2013 4:11 pm Post subject:

Thanks for your reply.

I'm sure it's mounted.

I can create a file in the NFS share from one computer and see it turning up on the problem computers (and vica versa!).
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ferg · Posted: Thu Mar 14, 2013 11:36 am Post subject:

Sorry to bump this but I've really no idea and cannot get to the bottom of this. Any ideas more than welcome?
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Climb up it, kayak down it + make sure it runs on GNU/Linux
"cease to exist, giving my goodbye, drive my car into the ocean,
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lexflex · Posted: Thu Mar 14, 2013 12:33 pm Post subject:

Hi,

Is there any difference in the way they are defined in /etc/exports or mounted in fstab?
(can you post all the options you used?)

Did you try unmounting and remounting manually?

Alex.

ferg · Posted: Thu Mar 14, 2013 12:43 pm Post subject:

Thanks for the comments.

I've tried manually unmounting/mounting and it makes no difference.

krinn · Watchman Joined: 02 May 2003 Posts: 7470

Try diff -u /etc/mtab /proc/mounts
Could try df -a too

ferg · Posted: Thu Mar 14, 2013 3:03 pm Post subject:

Thanks for that. "df -a" does show the missing but mounted NFS shares.

mtab also shows the missing drives (I'd forgotten about that file).

krinn · Watchman Joined: 02 May 2003 Posts: 7470

no, i was thinking maybe mtab was missing them.

Hu · Administrator Joined: 06 Mar 2007 Posts: 23076

/etc/mtab is a regular file and can be stale. /proc/mounts is a pseudofile that is always correct for the current mount namespace. If the mount is not in /proc/mounts, then it is not actually mounted. Many people prefer to replace /etc/mtab with a symlink to /proc/mounts for this reason. However, doing so can disrupt use of mounts that specify the user mount option.

ferg · Posted: Fri Mar 15, 2013 8:35 am Post subject:

Thanks for that.

/proc/mounts shows the missing volumes are indeed mounted. In fact the only tool that does not is running [b]df[/].

At this point I think I'll just ignore it and hope it goes away! Everything else appears to be working fine!

Thanks for everybody's input.

Cheers
Ferg
_________________
Climb up it, kayak down it + make sure it runs on GNU/Linux
"cease to exist, giving my goodbye, drive my car into the ocean,
you think I'm dead, but i sail away, on a wave of mutilation!"

wizzi · n00b Joined: 15 Mar 2008 Posts: 7 Location: Waterbury, VT

After examining the code, I believe the problem/feature (you decide) is that "duplicate" entries are now being removed from the df output (since coreutils 8.21). I too have a ReadyNAS and I believe we are both mounting subdirectories of the unit. Basically because it's just a big disk, the free/used/etc values are going to be the same even though they are different mount points.

The reason the particular entry shows up is that they used an election of "shortest name wins".

Personally I have yet to decide whether it's a problem or feature, but at least now we know. If we stick to the "do one thing and do it well" argument for *nix utilities, it's true we shouldn't be assuming that df will show mounted devices because they are different arenas.
Aaron