Re: 20001117: LDM Timeout Question

Unidata Support wrote:
> 
> ------- Forwarded Message
> 
> >To: <address@hidden>
> >From: "David Maggert" <address@hidden>
> >Subject: LDM Timeout Question
> >Organization: UCAR/Unidata
> >Keywords: 200011171705.eAHH5Co26058
> 
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> Dear Help Desk,
> 
> I have a question about LDM timeouts.  I have a troublesome LDM site in =
> Hawaii.  I have the -t option of rpc.ldmd set to 3600 (1 hour).  I =
> inserted files into the queue at Hawaii and requested those files from a =
> UNAVCO machine.  LDM sent some of the files in the first few minutes and =
> then there was a five minute gap where no files were sent.  Then when =
> LDM started sending files again it skipped several files in the queue on =
> Hawaii.  The -t parameter for rpc.ldmd is also 3600 on the UNAVCO =
> machine.  First of all, why is LDM skipping files when the timeout =
> doesn't appear to be exceeded?  It obviously had not been an hour since =
> those files were inserted into the queue.  What is the maximum value for =
> -t in the rpc.ldmd program?
> 
> Why do those skipped files start arriving at UNAVCO if I re-start LDM on =
> the UNAVCO machine?  Also, I have to re-start LDM on all downstream =
> nodes if I want those skipped files passed through the system.  Do I =
> need to set up my crontab to stop/start LDM everday on all my machines =
> so that I don't have files falling through the cracks or is there some =
> other timeout parameter that needs to be configured that I am missing?
> 
> Thanks,
> 
> David
> ---------------------------
> David Maggert
> University NAVSTAR Consortium (UNAVCO)
> Software Engineer/Programmer=20
> (303) 497-8055 Phone
> address@hidden
> =20
> 

Hi David,

It's not the -t option to rpc.ldmd that you want to use.   That option has to 
do with how long a site will wait for a response from a remote site when it 
does a remote procedure call, a pretty low level detail.  

You want to use the -m and/or -o option to tell rpc.ldmd how far back you want 
to request data. Here's something about this that I wrote to Karl Feaux at 
UNAVCO:

"The -o (offset) flag refers to what data you want to request upon start up, 
and the -m flag refers to what data you are willing to accept. (You might find 
yourself accepting older data than you would request if your ldm falls behind 
for some reason.)  By default, the offset will be the same as the max latency, 
which is what I assume you want, so using the -m flag should work."

You can see this message if you search our support archives - see 
http://www.unidata.ucar.edu/cgi-bin/mfs/65/3943?12#mfs.  And, do 'man rpc.ldmd' 
to see more information about these options and rpc.ldmd in general.

I'm not sure why your LDM received the missing files on startup but not during 
the normal course of events - I'd need to take a look at one or both of the 
logs for that.  But, I think that trying the above will solve your problem.  
So, no, you should not need to restart the LDM to get all the files.

Anne
-- 
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Anne Wilson                     UCAR Unidata Program            
address@hidden                 P.O. Box 3000
                                  Boulder, CO  80307
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