RE: nfsd and kswapd

["Amir Hermelin" <amir@montilio.com>]

BTW also I'm not running anything else significant other than knfsd, and =
it
appears that there isn't actual swapping going on.

Thanks,
Amir.


-----Original Message-----
From: Amir Hermelin [mailto:amir@montilio.com]=20
Sent: Monday, June 07, 2004 12:16 PM
To: 'Marc Schmitt'
Cc: 'nfs@lists.sourceforge.net'
Subject: RE: [NFS] nfsd and kswapd


Thanks Marc for the info.  It so happens I'm also using a PowerEdge =
(2600),
so I'll check out that thread.  I'm using a RH 9 system, kernel 2.4.20-8 =
-
should that include the better mem management you've mentioned?



-----Original Message-----
From: Marc Schmitt [mailto:mschmitt@inf.ethz.ch]=20
Sent: Monday, June 07, 2004 10:22 AM
To: Amir Hermelin
Cc: nfs@lists.sourceforge.net
Subject: Re: [NFS] nfsd and kswapd


Hi Amir,

On Mon, 2004-06-07 at 00:46, Amir Hermelin wrote:
> Hi,
> I'm observing a strange phenomenon running nfsd on 2.4.20 (RH).  I'm
> using a dual-Xeon server with 6GB of memory, and 40 nfsd threads=20
> running.  Under very heavy load, after a while kswapd starts=20
> constantly occupying between 60-90% cpu, and every once in a while=20
> keventd also wakes up with some 10- 30% of its own.  This obviously=20
> slows the system and greatly reduces the nfs performance.  The=20
> strangest thing is, that when I reduce the memory to 512MB (with the=20
> mem boot option), kswapd seems to be getting a lot less CPU.
>=20
> Any explanations on the matter would be greatly appreciated.

Is that a RH 7.3 system? If so, make sure you're running kernel =
2.4.20-28 or
later, it has the memory management of RH 9 backported and behaves much
better in a setup like yours.

There were many discussions about this on the Dell Linux PowerEdge list, =
one
thread started here:
http://lists.us.dell.com/pipermail/linux-poweredge/2003-May/024785.html

One workaround is to disable swap, not sure if that's on option for you
though. Depends on what you're running other than file serving.

Greetings,
     Marc



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