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[LDM #YUB-353996]: LDM question

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  • Subject: [LDM #YUB-353996]: LDM question
  • Date: Sun, 15 Feb 2009 20:51:36 -0700
Hi Mike,

re:
> I am seeing in my ldmd.log file, every 1 minute, that it switches primary
> feed source to the Alternate then back, continously.
> 
> I have two identical noaaport LDM servers which feed this computer (hp2).
> Here is a couple of minutes from the ldmd.log file.
> 
> Feb 16 02:56:34 AI-02 noaaport2.wright-weather.com[31823] NOTE: Switching
> data-product transfer-mode to primary
> Feb 16 02:56:34 AI-02 noaaport2.wright-weather.com[31823] NOTE: LDM-6
> desired product-class: 20090216015634.299 TS_ENDT {{NIMAGE|WSI|NLDN|WMO,
> ".*"},{NONE,  "SIG=1472a06231ce699e74416a5e65c904b6"}}
> Feb 16 02:56:34 AI-02 noaaport2.wright-weather.com[31823] NOTE: Upstream
> LDM-6 on noaaport2.wright-weather.com is willing to be a primary feeder
> Feb 16 02:57:15 AI-02 noaaport.wright-weather.com[31822] NOTE: Switching
> data-product transfer-mode to alternate
 ...

This is a completely natural occurrence when there are multiple upstream
feeders for identical sets of data when the product latency for each
upstream is nearly identical.  It is nothing to be worried about (unless
you don't like the plethora of logging).

> Here is relevant, ldmd.conf entries.
> 
> REQUEST NIMAGE|WMO ".*" noaaport.wright-weather.com
> REQUEST NIMAGE|WMO ".*" noaaport2.wright-weather.com

If you want the switching to stop, you can adjust one of your requests
to be a different representation of the same set of data.  For instance:

REQUEST NIMAGE|WMO ".*" noaaport.wright-weather.com
REQUEST NIMAGE|WMO "(.*)" noaaport2.wright-weather.com

> Is this normal for the LDM to switch back and forth every minute?

Yes, when the latency for the upstream feed sites are nearly idtentical.

> the
> noaaport servers are both receiving data via the S75 receiver, so in theory
> are getting the exact same products  at the exact same time.

Exactly.

> I am running LDM v 6.6.5

this behavior will be seen in LDM versions 6.4.5+.

> Thanks for your help, as always.

No worries.


Cheers,

Tom
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Ticket Details
===================
Ticket ID: YUB-353996
Department: Support LDM
Priority: Normal
Status: Closed