[ldm-users] 20080216: Nexrad Level 3 (cont.)

• To: "Tyler Allison" <tyler@xxxxxxxxxxxxxxxx>
• Subject: [ldm-users] 20080216: Nexrad Level 3 (cont.)
• From: Tom Yoksas <yoksas@xxxxxxxxxxxxxxxx>
• Date: Sat, 16 Feb 2008 22:52:16 -0700

Hi Tyler,

re:
>Since my system looks to be mimic'ing Jeff's I can chime in and say that
>it is definitely not IO related with my L3 system.
>
>My queue file is running in a memory based file system with the entire
>queue loaded into memory via a tmpfs file system.  That completely
>eliminates the IO issue you would see with placing the queue on disk.
>
>The only IO hit I take is when taking the data out of queue and writing to
>disk which is dedicated to LDM data. I have no downstream feeds.

This information eliminates I/O bottleneck concerns from your machine,
at least.

>pqmon shows max age of 6902 which leads me to believe the queue size is
>plenty big.

Yup, I agree.

>There has got to be an intermittent upstream issue somewhere. Those are
>always the worst ones to troubleshoot!

Given the latencies seen (excluding round-trip or recirculated
products), I would imagine that the problem is at the source -- when
the products are broadcast in NOAAPort.  This view is buoyed by an ADM
message that Darryl Herzmann sent along a little bit ago:

  NOUS72 KNCF 111452
  ADMNCF
  THE NWSTG IS EXPERIENCING TECHNICAL DIFFICULTIES WITH A FRONT END
  PROCESSOR.  THEY ARE TROUBLSHOOTING THE ISSUE AND HOPE TO HAVE
  THE PROBLEM RESOLVED IN A TIMELY FASHION.  THANK YOU FOR YOUR
  PATIENCE.

Enough fun for tonight ;-)

Cheers,

Tom
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• References:
  • Re: [ldm-users] 20080216: Nexrad Level 3 (cont.)
    • From: Tyler Allison