This archive contains answers to questions sent to Unidata support through mid-2025. Note that the archive is no longer being updated. We provide the archive for reference; many of the answers presented here remain technically correct, even if somewhat outdated. For the most up-to-date information on the use of NSF Unidata software and data services, please consult the Software Documentation first.
Hi Nancy, Yes, I will leave the allow on thelma until we resolve what we want to do..not a problem. However, <snip> I still don't quite understand why that outgoing message would be 4 times the size of the incoming data stream, <snip> This makes no sense unless you are feeding other sites..Do you have any allows in your ldmd.conf? <snip> Another curiousity that's poking up is that the number of data packets being received by mothra exceeds the number sent by thelma. This is resulting in a "Number of periods not equal" message at the LDM comparison site. <snip> This is also quite strange...is mothra requesting anything else from another site..i.e. NLDN from striker..? Please send me your ldmd.conf file, I think that is the best way for me to investigate... I went to ASU for a year in 1993 to get some physics behind me before going to grad school here at CU, and I know how ASU and U of A are like oil and water..:) Just a comic aside to the issues at hand of getting prompt data delivery from U of A.. Go Devils! Cheers, -Jeff ____________________________ _____________________ Jeff Weber address@hidden Unidata Support PH:303-497-8676 COMET Case Study Library FX:303-497-8690 University Corp for Atmospheric Research 3300 Mitchell Ln http://www.unidata.ucar.edu/staff/jweber Boulder,Co 80307-3000 ________________________________________ ______________________ On Thu, 27 Feb 2003, Nancy Selover wrote: > Jeff, > Our system administrator has been monitoring the traffic into and > out of mothra as he has been directing the Datacomm people to try and solve > our network slowness issues, particularly with getting the LDM data. Here > is his latest note. Is it possible to stay on thelma for a week to see if > it is stable. Also, do you know why we are getting more products than > thelma (per the upstream-downstream comparison website)? I would guess it > is a function of what products we keep rather than what's in the queue. > > Thanks, > Nancy > > Nancy J. Selover > Asst. State Climatologist > Office of Climatology tel: 480-965-0580 > Arizona State University fax: 480-965-1473 > Tempe, AZ 85287-1508 e-mail: address@hidden > > > -----Original Message----- > > From: Talbot Brooks > > Sent: Thursday, February 27, 2003 11:05 AM > > To: Nancy Selover > > Cc: Joseph Zehnder > > Subject: RE: Unidata update > > > > Well, it looks like you're getting your all of your data now. It's still > > a bit slow at times, but it looks like everything is coming through. Even > > if mothra is sending a message back to thelma, I still don't quite > > understand why that outgoing message would be 4 times the size of the > > incoming data stream, but I'll roll with it. Another curiousity that's > > poking up is that the number of data packets being received by mothra > > exceeds the number sent by thelma. This is resulting in a "Number of > > periods not equal" message at the LDM comparison site. > > > > Regardless, can you let things run from thelma for a week or two? If it > > stays "up", then I think our culprit is definitely at UofA or the link > > between here and there and not on the shoulders of our DataComm folks. If > > this does prove to be the case, I think the path of least resistance would > > be to leave our source as thelma and bag getting stuff from U of A - it's > > gonna be a nightmare trying to get that fixed... > > > > Thanks, > > > > Talbot Brooks > > ASU Dept. of Geography > > 600 E Orange St. > > Tempe, AZ 85287-0104 > > > > (480) 965-7832 > > address@hidden > > > > -----Original Message----- > > From: Nancy Selover > > Sent: Thursday, February 27, 2003 10:00 AM > > To: Talbot Brooks > > Cc: Joseph Zehnder > > Subject: RE: Unidata update > > > > Talbot, > > LDM has to constantly send messages to thelma (or whatever data > > server is upstream) requesting data. The upstream server responds to each > > request with a data stream, which then ends, and mothra asks for another > > one, etc. It's a continual series of processes that start and stop. > > Hourly there is a statistical report mothra sends out to ucar on > > latencies. As mothra gets the data in, it also starts and stops a series > > of decoders which decode various data types, as soon as it detects that > > they are in the queue. > > > > Nancy > > > > Nancy J. Selover > > Asst. State Climatologist > > Office of Climatology tel: 480-965-0580 > > Arizona State University fax: 480-965-1473 > > Tempe, AZ 85287-1508 e-mail: address@hidden > > > > -----Original Message----- > > From: Talbot Brooks > > Sent: Wednesday, February 26, 2003 5:16 PM > > To: Joseph Zehnder; Nancy Selover > > Subject: Unidata update > > > > Howdy - > > > > As of 5 pm, the discrepency report from Unidata between mothra and > > thelma shows minimal data missing and latencies under 500 seconds. Using > > eHealth to track network traffic to and from mothra shows a substantial > > increase in data transmission. So, it looks like you've been getting most > > of your product for at least the last 4-5 hours. > > > > However, there is something puzzling (at least to me) going on. The > > percentage of bandwidth used inbound is running at about 4%. The > > percentage of bandwidth outbound is as high as 18%. Any guess why there > > would be more outbound than inbound traffic? > > > > My take/educated guess: > > > > This suggests some sort of large-scale read activity taking place on > > the drive. If it were transmitting the results of that read back out, it > > could potentially account for the high outbound network traffic. If this > > is the case, I would single it out as the primary suspect for latencies as > > high as 500 seconds - the drive in mothra is at best a 10,000 rpm disk > > with a transfer rate around 9ms - the box is simply choking on rapid I/O. > > > > To kinda confirm, I went in and physically touched the box and > > watched the green drive light flicker on and off rapidly. This drive is > > in almost constant action. I can affirm that this trend is related to > > LDM, since all traffic dropped to zero when Nancy had LDM stopped earlier > > in the week. > > > > Thanks, > > > > Talbot Brooks > > ASU Dept. of Geography > > 600 E Orange St. > > Tempe, AZ 85287-0104 > > > > (480) 965-7832 > > address@hidden > > >