2008-02-05 18:08:20

by Frank van Maarseveen

[permalink] [raw]
Subject: Re: [PATCH 4/5] NFSD: Remove NFSD_TCP kernel build option

On Tue, Feb 05, 2008 at 12:50:39PM -0500, Trond Myklebust wrote:
> On Tue, 2008-02-05 at 16:50 +0100, Frank van Maarseveen wrote:
> > Last time I checked (around 2.6.22) writing large files on NFSv3 over
> > UDP was 20% faster compared to TCP (Gb LAN with one switch connecting
> > all machines).
> >
> > TCP and its timeout/retransmission behavior isn't always the best choice.
> If your environment has only 1 client working against a dedicated NFS
> server on a clean network, then that may indeed be the case, but as soon
> as you have more than 1 client, TCP almost always ends up outperforming
> UDP.

There are multiple clients (12 per physical server on average) but the
clients generally don't write (or read) at the same time. Anyway, I'll
keep this in mind.