All,
NCEP is indeed on internet2, which I presume would apply here.
A couple of noteworthy things.... I see some latency, but not for
everyone, and it doesn't seem to matter which conduit machine a
client is connected to. For example, with today's and yesterday's
gfs.t12z.pgrb2.0p25.f096 (hour 96) file here are the latencies per
client that I see:
11/12
Wisconsin: A few seconds
Unidata/UCAR: A few seconds
UIUC: 13 minutes
PSU: 27 minutes
11/13:
Wisconsin: A few seconds
Unidata/UCAR: A few seconds
UIUC: 2.33 minutes
PSU: 2.75 minutes
Another correlation is that UIUC and PSU (the ones with latency) are
only using one thread to connect to our conduit, whereas Wisc. and
Unidata use multiple threads.
At the moment this sort of has the appearance of a bottleneck
outside of NCEP. It might also be useful to see traceroutes from
UIUC and PSU to NCEP's CONDUIT. I know I saw some traceroutes
below. Can you try that and share with us?
Mike Shedlock
NCEP Central Operations
Dataflow Team
301.683.3834
On 11/13/2015 11:42 AM, Mike Dross
wrote:
My $ 0.02 from having works with LDM since the mid 90's.
I assume NCEP is not on internet2?
If so bandwidth shouldn't be an issue. Regardless I would check
the traceroutes to ensure a good path, high bandwidth, low
latency. Basic network topology check. I am sure you have done
this.
An iperf test is a simple way to test
the maximum throughput to see if bandwidth is an issue. If
that's not it, high latency or the way LDM is set up on the
upstream side is likely the culprit.
Mike
Sent from my iPad
Carissa,
Yes, still issues. There was a period several weeks
ago when throughput was clean, but recently we've seen
delays to varying degrees.
we've seen delays during 0.25 degree gfs transmission
that range from 500 seconds
to 3500 seconds over the past couple of days.
Also, comparison with
charts from other schools seem to show better reception when feeding from "conduit1" rather
than "conduit2".
Does this mean anything
to you or is it purely coincidence or incidental?
Thanks for any insights you can provide.
Art
Art,
I am going to add our team to this thread. Are you
still seeing issues. Is so we will take a look and
see if we can tell if anything on our side is
happening around FH 96.
--
Arthur A. Person
Research Assistant, System Administrator
Penn State Department of Meteorology
email: address@hidden, phone:
814-863-1563
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