20040821: NNEXRAD Feed

>From:  "Kevin R. Tyle" <address@hidden>
>Organization:  SUNY Albany
>Keywords:  200408211356.i7LDuKXn010407 IDD NNEXRAD

Kevin,

>We haven't received NNEXRAD products since around 0530 UTC today.
>Both of our immediate upstream servers, Cornell and PSU, feed
>from sunshine.ssec.wisc.edu, and neither appears to be receiving
>the products based on notifyme's.  However f5.meteor.wisc.edu
>is receiving them ok.  Is there perhaps a problem with sunshine?

The topology link on the real-time stats page for NNEXRAD data on gusher:

http://my.unidata.ucar.edu/cgi-bin/rtstats/iddstats_topo_nc?NNEXRAD+gusher.atmos.albany.edu

shows that PSU feeds from unidata2.ssec.wisc.edu, and it, in turn,
redundantly feeds from thelma.ucar.edu and sunshine.ssec.wisc.edu.  I
just ran a notifyme to unidata2 and see that it is receiving NNEXRAD
data with no problems.  At the same time a notifyme to the PSU machine
shows no NNEXRAD data in the past hour:

notifyme -vxl- -f NNEXRAD -o 3600 -h ldm.meteo.psu.edu

The volume plot of NNEXRAD data being received by PSU:

http://my.unidata.ucar.edu/cgi-bin/rtstats/iddstats_vol_nc?NNEXRAD+ldm.meteo.psu.edu

shows that it was receiving the full volume of NNEXRAD data until sometime
after 03Z and then the volume went to near zero.

At the same time, the volume plot of IDS|DDPLUS data on the PSU machine:

http://my.unidata.ucar.edu/cgi-bin/rtstats/iddstats_vol_nc?IDS|DDPLUS+ldm.meteo.psu.edu

shows a continuous record of data reception, so its LDM is, at least, running.

All of these clues suggest that the NNEXRAD ingest process on the PSU
machine is hung for some reason.  The initial corrective action that should
be taken is an LDM restart:

ldmadmin stop
ldmadmin start

A quick check of the Cornell IDD machines shows that neither is reporting
real-time statistics for the NNEXRAD feed.

If you have the bandwidth, I would recommend that you consider feeding
both from PSU and UW, at least until the LDM on the PSU machine is cycled.

Cheers,

Tom
--
+-----------------------------------------------------------------------------+
* Tom Yoksas                                             UCAR Unidata Program *
* (303) 497-8642 (last resort)                                  P.O. Box 3000 *
* address@hidden                                   Boulder, CO 80307 *
* Unidata WWW Service                             http://www.unidata.ucar.edu/*
+-----------------------------------------------------------------------------+