Subject: Re: NFS server problems on sparc/sparc64?
To: Matthias Scheler <firstname.lastname@example.org>
From: David Laight <email@example.com>
Date: 11/28/2007 22:50:42
On Wed, Nov 28, 2007 at 10:48:22AM +0000, Matthias Scheler wrote:
> NFS over UDP works very badly if the NFS server is faster than the client
> or has faster networking. My NetBSD-i386 NFS server (1Gb/s ethernet)
> managed to make my SPARCstation LX NFS client (10Mb/s ethernet) very
> unhappy until I switched to NFS over TCP.
Actually it is event worse if the client is faster than the server!
Unless you only run a single nfsd process, some requests get stalled
(I think by the disk access algorithms) and then timout ...
With only a single server process each request happens in seqeunce
so none get delayed a lot.
In the traces I've seen this is all made worse by Unix system often
buffereing file writes in the cache, then doing concurrent writes
for many 8k pages all at the same time.
David Laight: firstname.lastname@example.org