NFS Performance (was Re: [Beowulf] GPFS on Linux (x86))

Joe Landman landman at
Fri Sep 15 09:27:57 PDT 2006

Michael Will wrote:
> I am puzzled by an sles9sp3 (2.6.9 kernel) nfs server that serves rhel3 
> (2.4.21 kernel) compute nodes. For some reason a lot of times the mounts 
> fail (with default as well as modified parameters). The symptom is 
> mount: rpc timeout. The server logs all authentification requests as 
> successful.  The switch is an oversubscribed hp 4108gl.

Yes.  This is what we ran into last year.  A SuSE box serving a Rocks 
cluster (Rocks 4.0).  Basic idea: use tcp mounts and turn off jumbo 
packets.  Also, we had major issues with the tg3 driver, and moved the 
RHEL units to a BCM5700 driver.  After this, most of the problems went away.


Joseph Landman, Ph.D
Founder and CEO
Scalable Informatics LLC,
email: landman at
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phone: +1 734 786 8423
fax  : +1 734 786 8452 or +1 866 888 3112
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