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Re: 20011031: LDM latency

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  • Subject: Re: 20011031: LDM latency
  • Date: Mon, 05 Nov 2001 15:21:46 -0700
Patrick O'Reilly wrote:
> 
> > ****************************************************
> 
> Anne,
> 
> It seems the latency does vary over time.  It seems okay when I first arrive
> in the morning, but as things "get busy" it gets high.  Maybe it's a
> combination of the internet getting busy and lots of model data coming in by
> 8 or 9 a.m.  It seems to stay behind all day then maybe is "catching up"
> overnight when things are slower.  I am requesting UNIDATA feed from
> papagayo.unl.edu, and NNEXRAD but haven't gotten any Nexrad data yet.  I am
> working with Jeff on that.  We have been losing products, though from
> Saturday to today they are all there, as maybe the network is quiet over the
> weekend.  Could be a campus network issue?  We could increase the default
> latency value a bit until we get things figured out.  Thanks......
> 
> Patrick

Hi Patrick,

Well, earlier papagayo was showing latencies from 27 to 30 minutes.  If
papagayo's adding that much latency to every product, you're already
going to be behind.  However, right now it's running right on time. 
Hmmm...

(Did you know that you can check papagayo's timliness using notifyme? 
Here's what I did:

(anne) imogene:/local/ldm/bin 10 % notifyme -vl - -h papagayo.unl.edu
Nov 05 22:16:52 notifyme[13448]: Starting Up: papagayo.unl.edu:
20011105221652.365 TS_ENDT {{ANY,  ".*"}}
Nov 05 22:16:52 notifyme[13448]: NOTIFYME(papagayo.unl.edu): OK
Nov 05 22:17:12 notifyme[13448]:    13642 20011105221657.286 FNEXRAD
313  SDUS52 KMLB 052216 /pN0RMLB
       ********                                   ^^^^^^
Nov 05 22:17:15 notifyme[13448]:    19862 20011105221701.398 FNEXRAD
319  SDUS52 KMLB 052211 /pNCRMLB
Nov 05 22:17:42 notifyme[13448]:    13667 20011105221740.521 FNEXRAD
555  SDUS52 KMLB 052216 /pN0VMLB
Nov 05 22:17:52 notifyme[13448]:    14160 20011105221747.051 FNEXRAD
596  SDUS52 KMLB 052216 /pN0SMLB
Nov 05 22:18:02 notifyme[13448]:    13639 20011105221655.556 NNEXRAD
009  SDUS52 KMLB 052216 /pN0RMLB
Nov 05 22:18:03 notifyme[13448]:     5956 20011105221656.496 NNEXRAD
015  SDUS56 KMFR 052215 /pN0RMAX
Nov 05 22:18:04 notifyme[13448]:     6364 20011105221700.028 NNEXRAD
019  SDUS52 KTBW 052215 /pN0RTBW
Nov 05 22:18:04 notifyme[13448]:    11245 20011105221701.416 NNEXRAD
020  SDUS54 KOUN 052215 /pN0RFDR
Nov 05 22:18:05 notifyme[13448]:     7792 20011105221701.732 NNEXRAD
022  SDUS54 KTSA 052216 /pN0RSRX

The time under the *'s is the current time, and the time under the ^^^'s
is the time the product was first put into a product queue.  We call the
latter the injection time.  In the line that I annotated, we can see
that papagayo got the product 15 seconds after it was injected.  Not too
bad.)

Let's examine the connectivity between you and papagayo.  I recommend
that you run the ldm program 'netcheck'.  See the man page and let me
know if you have questions about it.

It may be that papagayo is a bad feed for you, regardless of the
connectivity between you and it.  But, before we search for a better
feed, lets gather a bit more evidence.

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