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RE: 20030227:ASU-Unidata update

Nancy, 

Thanks for the ldmd.conf..

Nothing in there explains the traffic anomalies described by your
sysadmin...most confusing.

Perhaps you could open a thread between us so we can further define what
problems, if any, still exist. I would think it impossible to get more
packets than thelma sends...and the outflow should not be in the same
magnitude as the inflow...all that goes out are rpc calls to identify
prods, and they are...obviously..much smaller than the data packets, and
the stats..which actually use a mail server to return back to us..so I
remain puzzled by the numbers previously mentioned.

I am sure that in the edu community, oppossed to the sporting one,
AZ schools cooperate quite nicely with each other..it was merely a jest :)

Hope you are enjoying the rain, we are loving the snow!

-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,
>       Here's the ldmd.conf file.  As far as I know we are feeding no one
> the data.  We do have another server NFS mounted onto mothra, also running
> gempak, accessing the real-time gempak datafiles, but not running ldm.
>       I went to UCLA many, many years ago, and I still consider it my alma
> mater, even though I've been here about 13 years.  I understand
> cross-town/intrastate rivalries, but in this case, it's just a matter of U
> of A have even more firewalls than ASU (hard to believe). 
> 
> 
> 
> 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: Jeff Weber [mailto:address@hidden]
> Sent: Thursday, February 27, 2003 12:34 PM
> To: Nancy Selover
> Cc: ldm-support
> Subject: 20030227:ASU-Unidata update
> 
> 
> 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
> > > 
> > 
> 
>