[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: Top level CONDUIT relay

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 Note that the archive is no longer being updated. We provide the archive for reference; many of the answers presented here remain technically correct, even if somewhat outdated.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.

  • Subject: Re: Top level CONDUIT relay
  • Date: Wed, 20 Jun 2007 12:03:44 -0400
Steve,
If you provide us a pqact.conf I can have the box chi set up to feed off of ldm1 and see how its latencies are. 

Justin
On Jun 20, 2007, at 11:36 AM, Steve Chiswell wrote:


Justin,

Since the change at 13Z by dropping daffy.unidata.ucar.edu out of the
top level nodes the ldm2 feed to NSF is showing little/no latency at
all. The ldm1 feed to NSF which is connected using the alternate LDM
mode is only devivering the .status messages its creates as all the
other products are duplicates of products already being received from
LDM2 and that is showing high latency:
http://www.unidata.ucar.edu/cgi-bin/rtstats/iddstats_nc? CONDUIT+atm.cise-nsf.gov 

This configuration is getting data out to the community at the moment.
The downside here is that it puts a single point of failure at NSF in
getting the data to Unidata, but
I'll monitor that end.

It seems that ldm1 is either slow, or it is showing network limitations
(since
flood.atmos.uiuc.edu is feeding from ncepldm which is apparently
pointing to ldm1, there is load on ldm1 besides the NSF feed. LDM2 is
feeding both NSF and idd.aos.wisc.edu (and Wisc looks good since 13Z as
well) so it is able to
handle the throughput to 2 downstreams, but adding daffy as the 3rd
seems to
cross some point in volume of what can be sent out.

Steve

On Wed, 2007-06-20 at 09:45 -0400, Justin Cooke wrote:

Thanks Steve,
Chi has set up a box on the lan for us to run LDM on, I am beginning to 
get things running on there.

have you seen any improvement since dropping daffy?

Justin

On Jun 20, 2007, at 9:03 AM, Steve Chiswell wrote:


Justin,

Yes, this does appear to be the case. I will drop daffy from feeding
directly and instead move it to feed from NSF. That will remove one
of the top level relays of data having to go out of NCEP and
we can see if the other nodes show an improvement.

Steve

On Wed, 20 Jun 2007, Justin Cooke wrote:


Steve,

Did you see a slowdown to ldm2 after Pete and the other sites began
making connections?
Chi, considering steve saw a good connection to ldm1 before the other 
sites connected doesn't that point toward a network issue?
All of our queue processing on the diskserver has been running without 
any problems so I don't believe anything on that system would
impacting
ldm1/ldm2.

Justin

On Jun 20, 2007, at 12:04 AM, Chi Y Kang wrote:
I setup the test LDM server for the NCEP folks to test the local pull from the LDM servers. That should give us some information / network or system related issue. We'll handle that tomorrow. I am a little bit concerned that the slow down all occurred at the some time as the 
ldm1 crash last week.

Also, can NCEP also check if there are any bad dbnet queues on the
backend servers?  Just to verify.



Steve Chiswell wrote:

Thanks Justin,
I also had a typo in my message:
ldm1 is running slower than ldm2
Now if the feed to ldm2 all of a sudden slows down if Pete and other sites add a request to it, it would really signal some sort of total 
bandwidth limitation
on the I2 connection. Seemed a little coincidental that we had a
show
period
of good connectivity to ldm1 after which it slowed way down.
Steve
On Tue, 2007-06-19 at 17:01 -0400, Justin Cooke wrote:

I just realized the issue. When I disabled the "pqact" process on
ldm2 earlier today it caused our monitor script (in cron, every 5
min) to kill the LDM and restart it. I have removed the check for
the pqact in that monitor...things should be a bit better now.

Chi.Y.Kang wrote:
Huh, i thought you guys were on the system. let me take a look on 
ldm2
and see what is going on.


Justin Cooke wrote:


Chi.Y.Kang wrote:


Steve Chiswell wrote:


Pete and David,

I changed the CONDUIT request lines at NSF and Unidata to
request data
from ldm1.woc.noaa.gov rather than ncepldm.woc.noaa.gov after
seeing
lots of
disconnect/reconnects to the ncepldm virtual name.
The LDM appears to have caught up here as an interim solution. 

Still don't know the cause of the problem.

Steve


I know the NCEP was stop and starting the LDM service on the
ldm2
box
where the VIp address is pointed to at this time.  how is the
current
connection to LDM1?  is the speed of the conduit feed
acceptable?


Chi, NCEP has not restarted the LDM on ldm2 at all today. But
looking
at the logs it appears to be dying and getting restarted by cron. 

I will watch and see if I see anything.

Justin







--
Chi Y. Kang
Contractor
Principal Engineer
Phone: 301-713-3333 x201
Cell: 240-338-1059



--
Steve Chiswell <address@hidden>
Unidata