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[LDM #QKY-452311]: National Weather Service Level II (Information Request)



Hi Donald,

> Our switch to a "consolidated" LDM scheme is nearly complete.  The
> solution we implemented was to aggregate on one of four machines and
> feed the other three as clients.  Our train of thought is that, Should
> we need to take the aggregation server off line, any of the other three
> could assume the role and would have a full queue of data.  This
> implementation goes back to the original problem of not having enough
> bandwidth for dual streams from each NEXRAD site.
> 
> We run a series of monitoring scripts that bring down the aggregation
> server and promote one of the clients to the aggregative role.  This
> "cut over" performed quickly & cleanly in our lab but seems somewhat
> lethargic on the operational servers as we have increased the number of
> NEXRAD sites.(120 of 140+ sites have been added to the system to date.)
> 
> We have noticed that sometimes at LDM startup from client to
> aggregation, ldmadmin watch doesn't show any packets being received
> (although ldmping shows RESPONDING). In fact, we've waited as long as 10
> minutes without getting any data. If we delete and recreate the queue
> and start again, the packets show up instantly.
> 
> What could be causing the delay? Since deleting/re-creating the queue
> doesn't show a delay, could it be related to LDM searching metadata for
> 140 separate IPs? The LDM is configured to go back 1 hour, although each
> location probably only has ~10 minutes worth of data. It just seems like
> we are missing something if the quickest option is to delete and
> recreate the queue.
> 
> Any insight would be appreciated.

What's the capacity of the product-queues at the radar sites (both in number of 
bytes and number of products)?

> - Don
> 
> --
> **********************************************************************
> *Donald J. Horvat               *  ____                              *
> *                               * /    \     _____     _______  _____*
> *Sr. Systems Engineer           *(      )   / ___  )  / ___  / / ___/*
> * Support Contractor            * \____/   / /__/ /  / /  / / / /    *
> *WSR-88D Radar Operations Center*  |\/|   / ___  <  / /  / / / /     *
> *                               *  |/\|  / /   / / / /__/ / / /___   *
> *1313 Halley Circle             *  |\/| /_/   /_/ /______/ /_____/   *
> *Norman, OK 73069               *  |/\|                              *
> *                               *   WSR-88D RADAR OPERATIONS CENTER  *
> **********************************************************************
> *Phone: (405) 573-3418          * e-mail: address@hidden   *
> *FAX:   (405) 573-3340          *                                    *
> **********************************************************************

Regards,
Steve Emmerson

Ticket Details
===================
Ticket ID: QKY-452311
Department: Support LDM
Priority: Normal
Status: Closed


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