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20000049: LDM question

>From: Robert Ballentine <address@hidden>
>Organization: SUNY Osego
>Keywords: 200004092018.OAA14145 LDM product queue

Bob,

>   I am running ldm-5.0.8 on a Pentium III under Linux Red Hat 5.2.  It has
>been running well for almost a year, but in the last week or so I keep
>getting hundreds of messages in my ldmd.log file of the form
>        snow[1415]: Deleting oldest to make space 36032 bytes
>where the number of bytes varies from one message to the next.

This is telling you that your LDM queue size is not big enough to hold
the incoming data before it can be disposed of (decoded, deleted, etc.).

>At this time
>I am getting the IDD feed from snow.cit.cornell.edu.  The data feed seems OK
>except for some latency in the afternoon, but I am wondering about the
>deleting messages.  I still have plenty of disk space left on the computer.

You need to:

<login as user running the 'LDM'>
ldmadmin stop
ldmadmin delqueue
<edit your ldmadmin file and increase the size of the queue.  Given the
recent additions to the gridded data that is being sent over the IDD,
a queue size of 250 MB is not unreasonable. Depending on what you are
requesting to be fed, this may go quite a bit higher.>
ldmadmin mkqueue
ldmadmin start

The unfortunate thing is that you will get all of the previous hour's
data from your upstream feeder.  There is no way around this.

>I thought it might help to increase the size of my product queue, so I
>raised it to 180 MBytes, but I still get the messages.  I did not change the
>size of my pqsurf.pq file which is about 5.3 MBytes.

You did the right thing, but it looks like you did not increase the size
enough.

>   Should I be concerned about these messages?

Yes.  When products in the queue are being deleted to make room for new
ones, you are losing data.

>If so, what should I do about them?

Keep increasing the queue size until the messages go away.

>What is being deleted anyway?

Products in the queue itself.

>   Thanks,
>   Bob Ballentine

Tom Yoksas