Re: degrading performance (NFS v.3 client)

From: Trond Myklebust
Date: Thu Jan 31 2008 - 17:44:47 EST



On Thu, 2008-01-31 at 16:09 +0100, Claude Frantz wrote:
> Hello !
>
> Please allow me to submit to you a question related to a system which
> is a NFS v3 client for a Netapp server. The home directories are
> NFS attached. The following behaviour occurs sometimes. The system
> becomes very slow. The load average is increasing but the most
> interesting observation is the increase of the %iowait. After
> reboot the system is running well for many days, then the problem
> occurs again.
>
> Any idea ?

Hi,

Have you tried analysing the NFS performances using Chuck's nfs-iostat
utility? You can pick up a copy at
http://oss.oracle.com/~cel/linux-2.6/2.6.24/

Try looking both at

nfs-iostat 10 --page
and
nfs-iostat 10 --attr

to see what the differences are between the 'fast' and 'slow' cases...

Cheers
Trond

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