Re: NFS performances

["J. Lewis Muir" <jlmuir%imca-cat.org@localhost>]

On 5/12/14, 10:03 AM, Emmanuel Dreyfus wrote:
> Hello
>
> I have a NFS setup with both NetBSD 6 client and server over a gigabit
> network. Theperformance seems week, even whle client, server and
> network are almost idle.
>
> The test: time dd if=/dev/zero of=test bs=1024k count=100
>
> Done on the NFS server itself:
>    5.31s real 0.00s user 0.39s system
>
> Done over NFS:
>    9.82s real 0.00s user 0.12s system
>
> The overhead looks huge. This is a UDP mount with a 1500 bytes MTU,
> ping is at 0.8 ms from a virtualized client, ang 0.28 ms for a
> physical one.
>
> Are the numbers reasonable? Should I consider a 59% NFS overhead as
> acceptable, or are there some parameters to tweak?

Hi, Emmanuel.

RHEL 5 machine writing to an NFS v3 mount over GigE (1500 MTU):
   1.22s real 0.00s user 0.06s system

That's way faster than even your local test.  So, I'd say your numbers
do not seem reasonable.

Have you already determined that the problem is with NFS, not the
network (e.g. by using netperf or maybe just "time dd if=/dev/zero
bs=1024k count=100 | ssh NFS_SERVER 'cat > test'")?

Lewis