Old SUN NFS performance papers.

[Björn Grönvall]

On Sat, 24 Jan 2004 21:14:51 -0500 (EST)
Robert Watson <rwatson at freebsd.org> 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.

One reason that FreeBSD users experience poor NFSv3/TCP performance is
that the defaults for rsize and wsize is unusually small, only
8k. Solaris and HP-UX defaults to 32k for a good reason. I guess TCP
simply needs a little bit more data to chew on to be efficient.

I tested this on 5.2-CURRENT and found that large file read
performance went up from 56Mbit/s to 80Mbit/s, an improvement by 43%.

I have written a patch that makes FreeBSD use the same defaults as
Solaris and HP-UX. Note that with NFSv3 there is no risk associated
with specifying to large values for [rw]size. The server automatically
limits these values in the fsinfo rpc. Patch is attached.

Cheers,
Björn

-- 
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Bjorn Gronvall (Björn Grönvall)                    /_______________/|
Swedish Institute of Computer Science              |               ||
PO Box 1263, S-164 29 Kista, Sweden                | Schroedingers ||
Email: bg at sics.se, Phone +46 -8 633 15 25          |      Cat      |/
Cellular +46 -70 768 06 35, Fax +46 -8 751 72 30   '---------------'
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