Large discrepancy in reported disk usage on USR partition

[Brendan Hart]

Now that you mention it, it *is* strange that the NFS mount was not listed
by the "df" function.

Try again after a fresh reboot:

#: df -h
Filesystem                         Size    Used   Avail Capacity  Mounted on
/dev/aacd0s1a                      496M    176M    280M    39%    /
devfs                              1.0K    1.0K      0B   100%    /dev
/dev/aacd0s1e                      496M     15M    441M     3%    /tmp
/dev/aacd0s1f                       28G    4.8G     21G    19%    /usr
/dev/aacd0s1d                      1.9G    430M    1.3G    24%    /var
server2:/storage/blah/foo/data/    397G    103G    262G    28%
/usr/home/development/mount/foobar

I guess I must have missed the final line when copying the output when I
first posted to the mailing list. And then when I replied Mel, I had already
nmounted the NFS dir when attempting the suggested fix, so it did not show
when I ran "df" again to double-check, and I did not realize what had
happened.

I apologise for any confusion caused.

Best Regards,
Brendan Hart

---------------------------------
Brendan Hart, Development Manager
Strategic Ecommerce Division
Securepay Pty Ltd
Phone: 08-8274-4000
Fax: 08-8274-1400 


-----Original Message-----
From: Jeremy Chadwick [mailto:koitsu at FreeBSD.org] 
Sent: Friday, 31 October 2008 12:02 PM
To: Brendan Hart
Cc: 'Mel'; freebsd-questions at freebsd.org
Subject: Re: Large discrepancy in reported disk usage on USR partition

On Fri, Oct 31, 2008 at 11:50:39AM +1030, Brendan Hart wrote:
> >> #: df -h
> >> Filesystem          Size    Used   Avail Capacity  Mounted on
> >> /dev/aacd0s1a       496M    163M     293M    36%    /
> >> devfs               1.0K    1.0K     0B      100%   /dev
> >> /dev/aacd0s1e       496M    15M      441M    3%     /tmp
> >> /dev/aacd0s1f        28G    25G      1.2G    96%    /usr
> >> /dev/aacd0s1d       1.9G    429M     1.3G    24%    /var
> 
> > Is this output untruncated? Is df really df or an alias to 'df -t
nonfs'?
> 
> Yes, it really is the untruncated output of "df -h". I also tried the 
> "df -t nonfs" and it gives exactly the same output as "df". What are 
> you expecting that is not present in the output ?
> 
> > Is it possible that nfs directory got written to /usr at some point 
> > in
> time? 
> > You would only notice this with du if the nfs directory is unmounted.
> > Unmount it and ls -al /usr/mountpoint should only give you an empty 
> > dir
> 
> Bingo!! That is exactly the problem. An NFS mount was hiding a 17G 
> local dir which had an old copy of the entire NFS mounted dir. I guess 
> it must have been written incorrectly to this standby server by RSYNC 
> before the NFS mount was put in place. I will add an exclusion to 
> rsync to make sure it does not happen again even if the NFS dir is not
mounted.
> 
> Thank you for your help, you have saved me much time rebuilding this
server.

Can either of you outline what exactly happened here?  I'm trying to figure
out how an "NFS mount was hiding a 17G local dir", when there's no NFS
mounts shown in the above df output.  This is purely an ignorant question on
my part, but I'm not able to piece together what happened.

-- 
| Jeremy Chadwick                                jdc at parodius.com |
| Parodius Networking                       http://www.parodius.com/ |
| UNIX Systems Administrator                  Mountain View, CA, USA |
| Making life hard for others since 1977.              PGP: 4BD6C0CB |



__________ Information from ESET NOD32 Antivirus, version of virus signature
database 3571 (20081030) __________

The message was checked by ESET NOD32 Antivirus.

http://www.eset.com

 

__________ Information from ESET NOD32 Antivirus, version of virus signature
database 3571 (20081030) __________

The message was checked by ESET NOD32 Antivirus.

http://www.eset.com