Old SUN NFS performance papers.

Robert Watson rwatson at FreeBSD.ORG
Sat Jan 24 18:17:03 PST 2004

On Mon, 19 Jan 2004, Willem Jan Withagen wrote:

> I had no responses to my recent question on the difference between NFS
> over UDP and TCP. So perhaps nobody cares?? 
> So I tried searching but have not found much yet.  Does anybody know
> where to find the white papers SUN once wrote about tuning NFS??? They
> should be at sun, but where??  All other suggestions to read are
> welcomed as well. 
> Given my last posting I'm building two machines to do some NFS benchmark
> testing on.  Suggestions on what people "always wanted to know (tm)" are
> also welcom, and I'll see if I can get them integrated.  I've found the
> benchmarks in /usr/ports, some might do so nice work as well. 
> If people are interested I'll keep them posted in performance@ --WjW

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)?

Robert N M Watson             FreeBSD Core Team, TrustedBSD Projects
robert at fledge.watson.org      Senior Research Scientist, McAfee Research

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