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20030514: LDM-6.0.10 use and real time statistics reporting (cont.)

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  • Subject: 20030514: LDM-6.0.10 use and real time statistics reporting (cont.)
  • Date: Wed, 14 May 2003 10:00:22 -0600
>From: James Murakami <address@hidden>
>Organization: UCLA
>Keywords: 200305121843.h4CIhU7U016942 LDM-6 IDD rtstats

Hi James,

>We've been running sundog for nearly a month now. I guess what I had in the 
>ldmd.conf was incorrect ("rtstats -d /home/ldm/logs -h 
>rtstats.unidata.ucar.edu"). I removed the "-d /home/ldm/logs" reference and I 
>saw the statistics page was updating properly.

Excellent.

I took a quick look at the real time stats from sundog, and see that
its clock is most likely off:

http://www.unidata.ucar.edu/staff/chiz/rtstats
  Statistcs by host
  http://www.unidata.ucar.edu/staff/chiz/rtstats/siteindex.shtml
    sundog.atmos.ucla.edu [6.0.10]
    
http://www.unidata.ucar.edu/staff/chiz/rtstats/siteindex.shtml?sundog.atmos.ucla.edu

Bring up the latency plot for any feed (like IDS|DDPLUS) and notice
that the lowest the latency goes is about 183 seconds.  Even though it
is possible that your latencies are always at least 3 minutes, it is
more likely that your system clock is off by that amount.

I have been advising sites to run 'ntpdate' from 'root's crontab
to set the clock once per hour _if_ they are not already running
xntpd.

Here is an example of how to run ntpdate out of root's cron:

0 * * * * /usr/sbin/ntpdate timeserver > /dev/null

You would replace 'timeserver' with the fully qualified hostname for
the time server you would access to set your clock.  Lists of Stratum
1 and 2 time servers can be found, respectively in:

Stratum 1::

http://www.eecis.udel.edu/~mills/ntp/clock1a.html

Stratum 2::

http://www.eecis.udel.edu/~mills/ntp/clock2a.html

I have been advising folks to look through these web pages and identify
a public Stratum 2 server that is "close" to you.  Using the time
service from these folks typically requires that you send them an
email that you are doing so.

Tom