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[IDD #GOK-818269]: Help -- NEXRAD3 feed no longer working, along with some GOES imagery from UNIWISC
- Subject: [IDD #GOK-818269]: Help -- NEXRAD3 feed no longer working, along with some GOES imagery from UNIWISC
- Date: Fri, 10 Sep 2010 12:40:30 -0600
Hi Gary,
Here are some numbers from the real-time statistics that Marcus' machine
is sending back to Unidata:
current data ingestion on gwoemul.wiu.edu:
Data Volume Summary for gwoemul.wiu.edu
Maximum hourly volume 481.502 M bytes/hour
Average hourly volume 247.684 M bytes/hour
Average products per hour 47720 prods/hour
Feed Average Maximum Products
(M byte/hour) (M byte/hour) number/hour
HDS 179.680 [ 72.544%] 391.790 12378.295
IDS|DDPLUS 40.204 [ 16.232%] 55.577 35288.318
UNIWISC 22.617 [ 9.131%] 29.568 26.659
DIFAX 3.360 [ 1.356%] 12.090 4.841
FSL2 1.823 [ 0.736%] 2.076 22.227
Comparison of all of the data that a site like Marcus' could request given
sufficient bandwidth:
Data Volume Summary for idd.unidata.ucar.edu
Maximum hourly volume 14155.751 M bytes/hour
Average hourly volume 6973.663 M bytes/hour
Average products per hour 249825 prods/hour
Feed Average Maximum Products
(M byte/hour) (M byte/hour) number/hour
CONDUIT 2471.870 [ 35.446%] 7245.773 64061.738
NEXRAD2 2175.907 [ 31.202%] 2917.550 62035.357
NEXRAD3 820.510 [ 11.766%] 1048.914 51436.000
NGRID 690.929 [ 9.908%] 1406.051 15980.810
HDS 253.852 [ 3.640%] 393.416 17838.524
FNMOC 226.990 [ 3.255%] 1312.805 1960.190
NIMAGE 134.981 [ 1.936%] 241.821 168.571
FNEXRAD 87.758 [ 1.258%] 109.766 72.405
IDS|DDPLUS 40.365 [ 0.579%] 55.577 35461.214
EXP 37.829 [ 0.542%] 65.342 330.786
UNIWISC 22.599 [ 0.324%] 29.568 26.786
DIFAX 3.305 [ 0.047%] 12.090 4.833
GEM 2.807 [ 0.040%] 26.388 192.476
LIGHTNING 2.129 [ 0.031%] 4.094 232.762
FSL2 1.830 [ 0.026%] 2.076 22.357
A careful examination of both listing above show a couple of key features:
1) Marcus is requesting a small fraction of the data that is available
2) even with the current data request, not all of the data being
requested is getting through
One of the key things we look at is a comparison of delivery latency
for two different streams of data, one of relatively low volume, and
one of a relative medium to high bandwidth:
IDS|DDPLUS receipt latencies on gwoeuml.wiu.edu (relatively low volume):
http://www.unidata.ucar.edu/cgi-bin/rtstats/iddstats_nc?IDS|DDPLUS+gwoemul.wiu.edu
HDS receipt latencies on gwoemul.wiu.edu (relative moderate to high volume):
http://www.unidata.ucar.edu/cgi-bin/rtstats/iddstats_nc?HDS+gwoemul.wiu.edu
I want to draw attention to the latencies seen at ~18Z each day:
- the latencies for the low volume feed are acceptable
- the latencies for the moderate volume feed are large enough that
data disappears from the upstream feed machine before it can
be sent to gwoemul
These two observations taken together are a classic signature of artificial
bandwidth limiting by packet shaping.
Cheers,
Tom
--
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Ticket Details
===================
Ticket ID: GOK-818269
Department: Support IDD
Priority: Normal
Status: Closed