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20040806: GEMPAK/LDM problem...

The most likely problems would be you don't have enough bandwidth to try to
receive all of Conduit (which can be as much as 1.8 GB an hour).

Looking at the reception stats for what I believe is your LDM:

http://my.unidata.ucar.edu/cgi-bin/rtstats/iddstats_nc?CONDUIT+d14-69-10-190.try.wideopenwest.com

you see frequent excursions even on the weekend where your latencies are so
large that your upstream likely no longer has the data by the time your LDM
could receive the data. You have values as large as 10,000 seconds, and even
today will see peaks during the main model times around 4000 seconds latency.

The best bet is to reduce the amount of data you are requesting to fit within
your limitations.

Steve Chiswell
Unidata User Support


On Fri, 6 Aug 2004, Robert Dewey wrote:

> Hello,
>
> I am having some troubles with the LDM, particularly the CONDUIT feed. I
> am always missing random grids from a gridded set (ETA/GFS/etc.). Here
> is an example of the 06Z ETA from this morning, I used GARP to loop
> hours 00 through 84:
>
> GEMPAK: [DG -7]  Input grid EMSL ^040806/0600F063 @0 %NONE cannot be found.
> GEMPAK: [DG -7]  Input grid EMSL ^040806/0600F069 @0 %NONE cannot be found.
> GEMPAK: [DG -7]  Input grid EMSL ^040806/0600F084 @0 %NONE cannot be found.
> GEMPAK: [DG -7]  Input grid EMSL ^040806/0600F063 @0 %NONE cannot be found.
> GEMPAK: [DG -7]  Input grid EMSL ^040806/0600F069 @0 %NONE cannot be found.
> GEMPAK: [DG -7]  Input grid EMSL ^040806/0600F084 @0 %NONE cannot be found.
> GEMPAK: [DG -7]  Input grid WND ^040806/0600F057 @500 %PRES cannot be found.
> GEMPAK: [DG -7]  Input grid WND ^040806/0600F060 @500 %PRES cannot be found.
> GEMPAK: [DG -7]  Input grid WND ^040806/0600F063 @500 %PRES cannot be found.
> GEMPAK: [DG -7]  Input grid WND ^040806/0600F069 @500 %PRES cannot be found.
> GEMPAK: [DG -7]  Input grid WND ^040806/0600F084 @500 %PRES cannot be found.
>
> As you can see, I am missing random grids. What could the problem be? I
> have set my product queue in the ldmadmin script to 2GB (thinking that
> maybe the data is being lost), with my physical memory being 1GB (I have
> an additional 2GB of SWAP, but this never gets used, the entire system
> usually never uses more than 900MB). I do not have any "accept" lines in
> my ldmd.con file, but I don't think that is the problem. I checked my
> ldmd.log files, and found these mixed in (quite frequently):
> _________________________________________________________________________________________________
> Aug 06 22:03:38 LDM weather2[2648]: Connected to upstream LDM-6
> Aug 06 22:03:38 LDM weather2[2648]: Upstream LDM is willing to feed
> Aug 06 22:11:47 LDM bigbird[2725]: ERROR: requester6.c:206: Connection
> to upstream LDM closed
> Aug 06 22:12:02 LDM weather2[2649]: ERROR: requester6.c:206: Connection
> to upstream LDM closed
> Aug 06 22:12:17 LDM bigbird[2725]: Desired product class:
> 20040806221107.220 TS_ENDT {{CRAFT,  ".(KDTX|KGRR|KIWX)"}}
>
> Aug 06 22:47:39 LDM weather2[2646]: Connected to upstream LDM-6
> Aug 06 22:47:39 LDM weather2[2646]: Upstream LDM is willing to feed
> Aug 06 22:48:46 LDM bigbird[2650]: ERROR: requester6.c:206: Connection
> to upstream LDM closed
> Aug 06 22:49:16 LDM bigbird[2650]: Desired product class:
> 20040806213319.386 TS_ENDT {{CONDUIT,  ".*"}}
> _________________________________________________________________________________________________
>
> I checked the RUC2 data, from the CONDUIT feed... And all of the grids
> seem to be there, so I am not sure what exactly the problem is, or what
> these error messages mean...
>
> Here is the LDM system stats:
>
> O/S: Fedora Core 2
> Processor: 1.8Ghz AMD Duron
> System RAM: 1GB DDR-2100 RAM, (2GB SWAP)
> Hard Drive: 80GB HDD (7200RPM)
> Connection: 3-4Mbps connection
>
> Thanks!
> Robert Dewey
>
>
>