Old SUN NFS performance papers.
dom at happygiraffe.net
Sun Jan 25 03:04:29 PST 2004
On Sat, Jan 24, 2004 at 09:14:51PM -0500, Robert Watson wrote:
> I haven't done much benchmarking on NFS lately, but something worth
> remembering is that people have spent a lot of time researching and
> optimizing TCP for a variety of connection types, whereas the NFS code
> basically has a static implementation of RPC backoff and flow control that
> hasn't evolved much. TCP is aware of things like the pathwise-mtu to the
> server and adapts, whereas UDP just loses packets due to fragmentation,
> especially if you are using larger block sizes. Please do post your
> discoveries on performance@, and perhaps we could build an NFS performance
> tuning section in the FreeBSD Handbook (or if there's not that much
> content, add it to the FAQ)?
I'm just playing with this... The first thing to note (probably) is to
check that you can ping your server with a similiar size packet to the
one you're using. I realised that my network isn't as robust as I
thought it was very quickly yesterday, when pinging my server with an 8k
packet. I was seeing 70% packet loss. The default ping showed no
problems at all.
The reason I mention it is that I'd been playing with NFS tuning because
I had been seeing lockups. But the fault really lies at a lower level
than NFS, it appears.
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