Re: nfs is very slow
On Thu, Aug 07, 2003 at 05:39:55PM +0200, Nicos Gollan wrote:
> On Thursday 07 August 2003 14:01, Gregor Stößer wrote:
> > I'm having some trouble with my nfs-server. Performance is very bad, but
> > all ather protocols (ftp, http, scp) are quite fast.
>
> ftp, http et al. use TCP connections while NFS per default uses UDP packets.
> More recent kernels have experimental support for NFS over TCP. In your case
> (fast network where latency is a very limiting factor), there might be a
> problem with NFS sending small packages and needing confirmation on every
> one, thus adding a huge overhead, while TCP scales better. If you find a way
> to increase packet sizes - gigabit ethernet should support around 65kB -, you
> might actually see a performance increase.
I'm using already read- and write sizes of 64kB, that's not the point.
But NFS over TCP might be worth trying. Nevertheless, my machine worked
without any problem for more than a year, so changing from UDP to TCP
might help, but there must be some other reason.
>
> And something that got me: be sure you are not running IDS software like
> snort, or if you need it, make sure it ignores NFS traffic. I had the problem
> that after some two minutes of nfs use, my root partition was mysteriously
> full. It turned out that snort wrote a detailed report on each and every
> packet the server received. I don't know if this had any impact on
> performance (relatively slow network), but I don't think a thing like this
> goes unpunished.
There is definitely no firewall, sniffer or anything else running in my
internal network, I have just a firewall on the network card with my
public address.
>
> --
> Got Backup?
Yes, of course !
>
Gregor
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Gregor Stößer email: gregor.stoesser@chemie.uni-karlsruhe.de
Institut für Anorganische Chemie
Universität Karlsruhe Tel: 0721/608 2988
Fax: 0721/608 4854
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