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

Michael Will mwill at
Fri Sep 15 09:28:22 PDT 2006

We are not using jumbo packets (they are not on by default, are they?)
I have tried both udp and tcp mounts, same symptom. The nics tested
syskonnect as well as tg3 and it behaved identically. 

-----Original Message-----
From: Joe Landman [mailto:landman at] 
Sent: Friday, September 15, 2006 9:28 AM
To: Michael Will
Cc: Brent Franks; Chris Samuel; beowulf at
Subject: Re: NFS Performance (was Re: [Beowulf] GPFS on Linux (x86))

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


Joseph Landman, Ph.D
Founder and CEO
Scalable Informatics LLC,
email: landman at
web  :
phone: +1 734 786 8423
fax  : +1 734 786 8452 or +1 866 888 3112 cell : +1 734 612 4615

More information about the Beowulf mailing list