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[LDM #XXW-990118]: LDM - Not your average latency problem

Hi Mike,

> Institution: SJSU Meteorology
> Package Version: ldm-6.4.4 feeding to ldm-6.4.5
> Operating System: 2.4.22-1.2115.nptlsmp feeding to 2.6.9-42.0.2.ELsmp
> Hardware Information: PC
> Inquiry: Hi Guys,
> This is related to a problem I was discussing with Steve Emmerson after the 
> Usercomm meeting.
> Symptoms:
> Extreme latencies feeding to sonoma technology:
> http://www.unidata.ucar.edu/software/idd/rtstats/siteindex.php?derecho.sonomatech.com
> from:
> http://www.unidata.ucar.edu/software/idd/rtstats/siteindex.php?rossby.met.sjsu.edu
> They have a small but dedicated pipe, 500 Kbps, so latency is expected, but 
> their feed volume goes way below the pipe limit. And yet, when the volume 
> goes way down, they show extreme latency. Then the products will not even 
> come in. If I restart both LDM's on either end, then data begins flowing. The 
> problems seems to be related to long residence times of products in my queue, 
> and somehow the processes associated with getting that old data get hung. 
> Notice how on the feed volume chart for Sonoma tech, the UNIWISC volume 
> dissapears...but that should never happen...especially if the total volume is 
> so low.

I notice from the LDM log file on Rossby that the connections to Sonoma 
sometimes break several times per hour.  Is there any indication in Sonoma's 
LDM log file as to why this occurs?

Steve Emmerson

Ticket Details
Ticket ID: XXW-990118
Department: Support LDM
Priority: Normal
Status: Closed

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