Re; NFS performance

Rick Macklem rmacklem at
Sun Jan 9 19:06:53 UTC 2011

> It has been suggested that I move this thread to freebsd-stable. The
> thread so far (deficient NFS performance in FreeBSD 8):
> I updated my kernel to FreeBSD 8.2-PRERELEASE. This improved my
> throughput, but still not to the level I got from 7.3-STABLE. Here's
> an updated table from my original message:
> Observed bytes per second (dd if=filename of=/dev/null bs=65536):
> Source machine: mattapan scollay sullivan
> Destination machine:
> wonderland/7.3-STABLE 870K 5.2M 1.8M
> wonderland/8.1-STABLE 496K 690K 420K
> wonderland/8.2-PRERELEASE 800K 1.2M 447K
> Furthermore, I was still able to induce the NFS "server not
> responding"
> message with 8.2-PRERELEASE. So I applied the patch from Rick Macklem.
> The throughput did not change, but I haven't seen the NFS "server not
> responding" message yet.

So, did the patch get rid of the 1min + stalls you reported earlier?

Beyond that, all I can suggest is trying to fiddle with some of the
options on the net device driver, such as rxcsum, txcsum and tso.
(I think tso has had some issues for some drivers, but I don't know
 any specifics.) When I've seen poor NFS perf. it has usually been a
problem at the network device driver level. (If you have a different
kind of network card handy, you could try swapping them. Basically
one with a different net chipset so that it uses a different net device


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