From: Ian Kent <raven@themaw.net>
Subject: Re: NAS server avalanche overload
Date: Thu, 4 Mar 2004 22:38:08 +0800 (WST)
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To: Erik Walthinsen <omega@pdxcolo.net>
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On Wed, 3 Mar 2004, Erik Walthinsen wrote:

> On Wed, 2004-03-03 at 20:39, Ian Kent wrote:
> > Bumping the number of threads to 32 or 64 or more would be the first 
> > thing I would try.
> 
> Only problem is that if the spike occurs anyway, the load will be 33 or
> 65 instead of 17.  I don't know if it's ctxswitching itself to death
> while all these nfsd's are blocking, but if so, doubling or quadrupling
> the number of blocked processes will just make the spike worse.

I'm assuming there is not a problem with the NFS implementation of course.
Never the less you generally need many more than 16 threads for a busy 
NFS server.

> 
> Also, I've learned to be extremely careful about messing with nfsd while
> clients are connected.  I've had cases where just running exportfs

I wouldn't change this on the fly either. I'm suggesting this type 
of change be made when during scheduled downtime.

Ian



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