Hi Wido,
What is the full topology? Are you using a north-south or east-west? So far I've seen the east-west are slightly slower. What are the fabric modes you have configured? How is everything connected? Also you have no information on the OS - if I remember correctly there was a lot of improvements in the latest kernels...
And what about the bandwith?
The values you present don't seem awfully high, and the deviation seems low.
On Thu, Nov 6, 2014 at 1:18 PM, Wido den Hollander <wido@xxxxxxxx> wrote:
Hello,
While working at a customer I've ran into a 10GbE latency which seems
high to me.
I have access to a couple of Ceph cluster and I ran a simple ping test:
$ ping -s 8192 -c 100 -n <ip>
Two results I got:
rtt min/avg/max/mdev = 0.080/0.131/0.235/0.039 ms
rtt min/avg/max/mdev = 0.128/0.168/0.226/0.023 ms
Both these environment are running with Intel 82599ES 10Gbit cards in
LACP. One with Extreme Networks switches, the other with Arista.
Now, on a environment with Cisco Nexus 3000 and Nexus 7000 switches I'm
seeing:
rtt min/avg/max/mdev = 0.160/0.244/0.298/0.029 ms
As you can see, the Cisco Nexus network has high latency compared to the
other setup.
You would say the switches are to blame, but we also tried with a direct
TwinAx connection, but that didn't help.
This setup also uses the Intel 82599ES cards, so the cards don't seem to
be the problem.
The MTU is set to 9000 on all these networks and cards.
I was wondering, others with a Ceph cluster running on 10GbE, could you
perform a simple network latency test like this? I'd like to compare the
results.
--
Wido den Hollander
42on B.V.
Ceph trainer and consultant
Phone: +31 (0)20 700 9902
Skype: contact42on
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