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Re: RSA Comm Test (Weather - JSC) LDM Troubleshooting


>Date: Tue, 31 Jan 2006 08:38:13 -0600
>From: "Biggerstaff, Brice A9" <address@hidden>
>Organization: Lockheed-Martin Space Operations
>To: Steve Emmerson <address@hidden>,
>To: "Petit, Jackie" <address@hidden>
>Subject: RE: RSA Comm Test (Weather - JSC) LDM Troubleshooting

The above message contained the following:

>   Thanks for the information about the multi-homed servers.  I am
> enclosing the reciprocal logs for the timeframe that Jackie sent you.
> They are tar'd up and gzipped.  When you unzip it, there won't be a
> '.tar' extension, but it is a standard tar file.  To clarify some
> information about our situation.  The "SA" and "GP" files that Jackie
> referred to are all transmitted as LDM "EXP" files.  Internally they are
> surface observation and GPsonde balloon data respectively, in ASCII
> format.  On my side I am putting them in using a simple pqinsert
> manually.  Jackie is 'bent-piping' a data feed of similar data files
> from local data receivers, wind sensors, radar profilers, etc., all in
> ASCII files transmitted as LDM EXP.  She receives the data feed from her
> local systems and I can see that her server is getting it by using a
> notifyme command on our server, which you will be able to see when you
> check the logs.  However, none of the data is ever received at either
> end.  Until Friday that is.  On Friday Jackie was able to receive two of
> the surface ob files, but she never received any of the balloon files
> that I tried to send.  The major difference between the surface ob files
> and the balloon files, as I see it, is size.  Surface ob files are ~ 240
> bytes and the balloon files are ~18K.  

First off, there appears to be a problem with the clocks on either host
Rsaintrf or host Ftpsvr.  Ftpsvr's LDM log file contained this:

    Jan 27 21:10:41 ftpsvr rsaintrf[20183] NOTE: Upstream LDM-6 on 
rsaintrf.midds.jsc.nasa.gov is willing to be a primary feeder 

There were no corresponding entries in Rsaintrf's LDM log file
at about the same time  (assuming that host Rsaintrf and host
Rsaserv are the same computer.  Are they?).

The LDM system works best when clocks are accurate.  We recommend
running an Network Time Protocol daemon (e.g., ntpd(8)).  I don't think
that this is the cause of your problems -- but it definitely should be
fixed (it certainly makes it MUCH more difficult to diagnose problems).

>   I didn't get a chance to poke Brian about getting to Tom Yoksas at the
> AMS conference, but I'm sure he will if he gets a chance.  As for
> letting you login in to the systems, the Cape system doesn't have any
> Internet connection that I'm aware of and ours is a restricted no
> incoming login, so that won't be doable, I'm afraid.  Appreciate your
> time and assistance, Steve. We are just not seeing what we expect from
> our experience.

The LDM is known to work, so we just have to figure-out what in
your situation is causing problems.

What are the outputs of the following commands executed as the LDM
user on host rsaintrf.midds.jsc.nasa.gov?

    echo $PATH
    uname -a
    ldmadmin config
    ls -l $HOME/bin/rpc.ldmd
    ldmping -i 0 ftpsvr.er-rsaiia-unc.int

What ALLOW entries in the LDM configuration-file, "etc/ldmd.conf", allow
host ftpsvr.er-rsaiia-unc.int to request data?

> Thanks again,
>   Brice
> Brice Biggerstaff
> Johnson Space Center MIDDS Support
> Lockheed-Martin Space Operations
> 281-853-3011 (ofc.)
> 713-764-2601 (pager) 

Steve Emmerson

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