quota mismatch for NFS mount of XFS filesystem

[Liam Forbes]

I searched the archives, but didn't find anything about incorrect
quota information for an NFS mounted XFS filesystem.  I hope somebody
might have an idea.

We have a RHEL 5.7 server mounting a 15T XFS filesystem and exporting
it to RHEL 5.6 and 5.7 clients.  quota and xfs_quota on the server
show a user using ~5.8T, but quota on a client only shows ~1.8T.

Server:
nfs2:~$ cat /etc/redhat-release
Red Hat Enterprise Linux Server release 5.7 (Tikanga)
nfs2:~$ uname -a
Linux nfs2 2.6.18-274.3.1.el5 #1 SMP Fri Aug 26 18:49:02 EDT 2011 x86_64 x86_64
nfs2:~$ rpm -qa | grep xfsprogs
xfsprogs-2.9.4-1.el5.centos
nfs2:~$ sudo quota -s -v -u krieger
Disk quotas for user krieger (uid 3105):
     Filesystem  blocks   quota   limit   grace   files   quota   limit   grace
/dev/mapper/primaryfs_vg-primaryfs
                  5901G       0       0            310k       0       0
nfs2:~$ sudo /usr/sbin/xfs_quota
xfs_quota> quota -u -h krieger
Disk quotas for User krieger (3105)
Filesystem   Blocks  Quota  Limit Warn/Time    Mounted on
/dev/primaryfs_vg/primaryfs
               5.8T      0      0  00 [------] /export/wrkdir20
xfs_quota> quit

Client:
pacman1:~$ cat /etc/redhat-release
Red Hat Enterprise Linux Server release 5.6 (Tikanga)
pacman1:~$ uname -a
Linux pacman1 2.6.18-238.19.1.563g0000.el5 #1 SMP Fri Jul 15 20:26:36
EDT 2011 x86_64 x86_64 x86_64 GNU/Linux
pacman1:~$ sudo quota -s -v -u krieger
Disk quotas for user krieger (uid 3105):
     Filesystem  blocks   quota   limit   grace   files   quota   limit   grace
nfs2:/export/wrkdir20
                  1806G       0       0            310k       0       0

Could there be a miscalculation due to differing block sizes?  Other
suggestions of what to look at?  I'm not seeing any errors in logs
(which doesn't surprise me).

-- 
Regards,
-liam

-There are uncountably more irrational fears than rational ones. -P. Dolan
Liam Forbes       HPC Systems Analyst,      HPC&S Group Leader,      CISSP
ARSC, U of AK, Fairbanks   lforbes at arsc.edu 907-450-8618 fax: 907-450-8605