Re: [ldm-users] NEXRAD2/NEXRAD3 lag?

No joy there.  Our providers (TAMU, OU, WISC, et al) are all under tier 1
providers, and there is no lag.

I can't find the document that describes how the NEXRAD2 data is fed into
the LDM system.  I think it happens in DC at the Internet2 aperture, but
that information may be out of date (or I may be remembering it wrong).

As I recall, two weeks ago, we weren't the only ones seeing this lag.

And we're still seeing it on three servers with three separate upstream
providers -- and each server is deliberately on different BGP/backbone
providers for geographic AND network diversity.

Something's not quite right, and I think the key is understanding how the
NEXRAD2 data gets into LDM...and then going to THAT source to find out why
it's delayed.  I know Allison House's data isn't delayed (whereas iastate's
is), so my guess is they're acquiring it independently of LDM.

So we know iastate.edu is getting data 10 minutes late just like we are, as
are our upstream providers...but the servers themselves are always at 0 or
1 second of lag.

Something is definitely wrong.  We don't see any lag on any of the other
feed trees (HDS, IDS, WMO, NGRID, UNIWISC, NEXRAD3, etc).  This seems to be
unique to NEXRAD2.

Can someone from UCAR/UNIDATA jump in and help us...or should we open a
formal support ticket?


On Sun, May 11, 2014 at 5:49 PM, Steven Emmerson
<emmerson.steven@xxxxxxxxx>wrote:

> It could be that the last NEXRAD2 data-product is stuck in a system
> buffer. Try putting a "-flush" or "-close" on the relevant PIPE action.
> On May 11, 2014 11:49 AM, "Gilbert Sebenste" <
> sebenste@xxxxxxxxxxxxxxxxxxxxx> wrote:
>
>> Hi Blair,
>>
>>  We are still seeing this.  I know the TOC was made aware of this issue
>>> two
>>> weeks ago, but despite all our servers being 0 seconds lagged on the
>>> NEXRAD2 feed tree, our data (from multiple providers who are also not
>>> lagged) is at least 10 minutes behind.
>>>
>>
>> Been off the grid, for the most part, or I would have answered earlier.
>> Things to look for:
>>
>> Can you do a traceroute to the servers in question? See if anything is
>> jammed up inbetween them and you.
>>
>> Are all network cards set at least at 100 mb? If 10 mb, it can't handle
>> it.
>>
>> Is the system clock correct? Are you using ntp? This is a must.
>>
>>  Also, this page is a 500 internal server error and has been for months,
>>> and nobody has fixed it or seems to even notice:
>>> http://rtstats.unidata.ucar.edu/cgi-bin/rtstats/rtstats_topogif?NEXRAD2
>>>
>>> And this one takes over a minute to load:
>>> http://rtstats.unidata.ucar.edu/cgi-bin/rtstats/rtstats_feedtree?NEXRAD2
>>>
>>> ...but you can verify from the second link that we're not lagging (search
>>> for "tampa" or "chicago").
>>>
>>
>> Give those a try aboove, and see what happens.
>>
>> Gilbert
>>
>> ************************************************************
>> *******************
>> Gilbert Sebenste
>>  ********
>> (My opinions only!)
>>  ******
>> Staff Meteorologist, Northern Illinois University
>>  ****
>> E-mail: sebenste@xxxxxxxxxxxxxxxxxxxxx
>>  ***
>> web: http://weather.admin.niu.edu                                      **
>> Twitter: http://www.twitter.com/NIU_Weather                            **
>> Facebook: http://www.facebook.com/niu.weather                           *
>> ************************************************************
>> *******************
>>
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Blair Trosper
  Updraft Networks / Weather Data
  NOC:  469-844-5440
  Early Watch Notifications:  http://twitter.com/weatherwatches
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