Stonie,
We've got things reversed--our NTP server is the final receptor and our
four NOAAport systems synch off that server. The times in our filenames
are pulled right from the headers. The directory listing times are times
that the files were received by the server. As I indicated, the NOAAPORT
machine feeding the LDM on the server buffers the data in one minute
files and then dumps the buffer files at one minute intervals for LDM
ingest on the server. It seems to do this at 30 seconds after the
previous minute's buffer has been built. Hence, the data actually do
come in "at least" a minute (since seconds aren't recorded) earlier.
It's certainly close enough to real-time for our purposes.
We used to grab the data via NFS directly from the NOAAport ingestor,
but our hard drives are now way too small to hold very much data because
of the deluge from the new NIDS products, so we now move them over to a
server where we have a large RAID system, which allows us to store all
products from all the NIDS sites for a much longer period.
Jim
--
James P. Koermer E-Mail: koermer@xxxxxxxxxxxxxxxxx
Professor of Meteorology Office Phone: (603)535-2574
Natural Science Department Office Fax: (603)535-2723
Plymouth State College WWW: http://vortex.plymouth.edu/
Plymouth, NH 03264
"Stonie R. Cooper" wrote:
>
> Dr. Koermer and Robert,
>
> Are you experiencing any clock drift? I've matched your entries below with
> what we are seeing on our MetBox, which is separated by a couple of LDM jumps
> from our NOAAPort. It may be a hardware difference, also - big hardware,
> obviously, will keep up better. Our NOAAPort is the NTP server for our
> network, syncing to the NOAAPort time sync messages - we are seeing a two
> minute difference from what you are seeing:
>
> On Thursday 29 November 2001 17:45, Jim Koermer wrote:
> > From what I see over our NOAAport system, there is several minutes of
> > delay for some products. Here is part of a directory listing for one
> > site (GYX):
> >
> > -rw-r--r-- 1 ldm usr 4937 Nov 29 17:35 0111291730_NTP.nid
>
> -rw-r--r-- 1 ldm pdi 4923 Nov 29 17:33 ./NTP/NTP_20011129_1730
>
> > -rw-r--r-- 1 ldm usr 7123 Nov 29 17:35 0111291730_N3S.nid
>
> -rw-r--r-- 1 ldm pdi 7109 Nov 29 17:33 ./N3S/N3S_20011129_1730
>
> > -rw-r--r-- 1 ldm usr 5553 Nov 29 17:35 0111291730_N1P.nid
>
> -rw-r--r-- 1 ldm pdi 5539 Nov 29 17:33 ./N1P/N1P_20011129_1730
>
> > -rw-r--r-- 1 ldm usr 9689 Nov 29 17:34 0111291730_N3R.nid
>
> -rw-r--r-- 1 ldm pdi 9675 Nov 29 17:33 ./N3R/N3R_20011129_1730
>
> > -rw-r--r-- 1 ldm usr 7948 Nov 29 17:34 0111291730_N2S.nid
>
> -rw-r--r-- 1 ldm pdi 7934 Nov 29 17:32 ./N2S/N2S_20011129_1730
>
> > -rw-r--r-- 1 ldm usr 10856 Nov 29 17:34 0111291730_N2R.nid
>
> -rw-r--r-- 1 ldm pdi 10842 Nov 29 17:32 ./N2R/N2R_20011129_1730
>
> > -rw-r--r-- 1 ldm usr 9663 Nov 29 17:33 0111291730_N1S.nid
>
> -rw-r--r-- 1 ldm pdi 9649 Nov 29 17:32 ./N1S/N1S_20011129_1730
>
> > -rw-r--r-- 1 ldm usr 9788 Nov 29 17:33 0111291730_N1V.nid
>
> -rw-r--r-- 1 ldm pdi 9774 Nov 29 17:31 ./N1V/N1V_20011129_1730
>
> > -rw-r--r-- 1 ldm usr 11717 Nov 29 17:33 0111291730_N1R.nid
>
> -rw-r--r-- 1 ldm pdi 11703 Nov 29 17:32 ./N1R/N1R_20011129_1730
>
> > -rw-r--r-- 1 ldm usr 10595 Nov 29 17:33 0111291730_N0S.nid
>
> -rw-r--r-- 1 ldm pdi 10581 Nov 29 17:31 ./N0S/N0S_20011129_1730
>
> > -rw-r--r-- 1 ldm usr 13112 Nov 29 17:32 0111291730_N0V.nid
>
> -rw-r--r-- 1 ldm pdi 13098 Nov 29 17:31 ./N0V/N0V_20011129_1730
>
> > -rw-r--r-- 1 ldm usr 9398 Nov 29 17:32 0111291730_N0Z.nid
>
> -rw-r--r-- 1 ldm pdi 9384 Nov 29 17:30 ./N0Z/N0Z_20011129_1730
>
> > -rw-r--r-- 1 ldm usr 14439 Nov 29 17:32 0111291730_N0R.nid
>
> -rw-r--r-- 1 ldm pdi 14425 Nov 29 17:30 ./N0R/N0R_20011129_1730
>
> > -rw-r--r-- 1 ldm usr 19051 Nov 29 17:32 0111291724_NCR.nid
>
> -rw-r--r-- 1 ldm pdi 19037 Nov 29 17:30 ./NCR/NCR_20011129_1724
>
> > -rw-r--r-- 1 ldm usr 634 Nov 29 17:31 0111291724_NVL.nid
>
> -rw-r--r-- 1 ldm pdi 620 Nov 29 17:29 ./NVL/NVL_20011129_1724
>
> > -rw-r--r-- 1 ldm usr 2447 Nov 29 17:31 0111291724_NVW.nid
>
> -rw-r--r-- 1 ldm pdi 2433 Nov 29 17:29 ./NVW/NVW_20011129_1724
>
> > -rw-r--r-- 1 ldm usr 1243 Nov 29 17:31 0111291724_NET.nid
>
> -rw-r--r-- 1 ldm pdi 1229 Nov 29 17:29 ./NET/NET_20011129_1724
>
> > -rw-r--r-- 1 ldm usr 4964 Nov 29 17:29 0111291724_NTP.nid
>
> -rw-r--r-- 1 ldm pdi 4950 Nov 29 17:27 ./NTP/NTP_20011129_1724
>
> > -rw-r--r-- 1 ldm usr 5530 Nov 29 17:29 0111291724_N1P.nid
>
> -rw-r--r-- 1 ldm pdi 5516 Nov 29 17:27 ./N1P/N1P_20011129_1724
>
> > -rw-r--r-- 1 ldm usr 6764 Nov 29 17:29 0111291724_N3S.nid
>
> -rw-r--r-- 1 ldm pdi 6750 Nov 29 17:27 ./N3S/N3S_20011129_1724
>
> > -rw-r--r-- 1 ldm usr 9597 Nov 29 17:28 0111291724_N3R.nid
>
> -rw-r--r-- 1 ldm pdi 9583 Nov 29 17:27 ./N3R/N3R_20011129_1724
>
> > -rw-r--r-- 1 ldm usr 7767 Nov 29 17:28 0111291724_N2S.nid
>
> -rw-r--r-- 1 ldm pdi 7753 Nov 29 17:26 ./N2S/N2S_20011129_1724
>
> > -rw-r--r-- 1 ldm usr 10727 Nov 29 17:28 0111291724_N2R.nid
>
> -rw-r--r-- 1 ldm pdi 10713 Nov 29 17:26 ./N2R/N2R_20011129_1724
>
> > -rw-r--r-- 1 ldm usr 9639 Nov 29 17:27 0111291724_N1V.nid
>
> -rw-r--r-- 1 ldm pdi 9625 Nov 29 17:26 ./N1V/N1V_20011129_1724
>
> > -rw-r--r-- 1 ldm usr 9108 Nov 29 17:27 0111291724_N1S.nid
>
> -rw-r--r-- 1 ldm pdi 9094 Nov 29 17:26 ./N1S/N1S_20011129_1724
>
> > -rw-r--r-- 1 ldm usr 11581 Nov 29 17:27 0111291724_N1R.nid
>
> -rw-r--r-- 1 ldm pdi 11567 Nov 29 17:25 ./N1R/N1R_20011129_1724
>
> > -rw-r--r-- 1 ldm usr 11126 Nov 29 17:27 0111291724_N0S.nid
>
> -rw-r--r-- 1 ldm pdi 11112 Nov 29 17:25 ./N0S/N0S_20011129_1724
>
> > The filetimes can be about a minute later than when the data actually
> > arrive on our actual NOAAport system, since the raw data for a 1-minute
> > interval are put into a file and then sent to my server (listing above)
> > and acquired via ldm. There is so much data that it can't be
> > instantaneous, especially since the NWSTG channel also handles all
> > conventional data and model data. The precip data does seem to lag the
> > N0R data and probably due to the order inwhich the products are
> > transmitted. Note: the times in the filenames above do correspond to
> > data observation times.
> >
> > Jim
>
> Our LDM server is also distributing the other three NOAAPort channels - both
> GOES channels, and the DCP channel (has great AK Eta output). As Dan had
> explained earlier, the N0* products will be the quickest, as the CCB/WMO/RFP
> time stamp is applied to the beginning of the entire volume scan - not each
> elevation sweep.
>
> We are seeing the N0* products in near real-time on NOAAPort, so it could be
> a clock issue.
> --
> Stonie R. Cooper,
> Science Officer
> Planetary Data, Incorporated
> 3495 Liberty Road
> Villa Rica, Georgia 30180
> ph. (770) 456-0700; pg. (888) 974-5017; fx. (770) 459-0016
