On 3/14/2012 3:03 AM, unruh wrote:
On 2012-03-13, Ron Frazier (NTP)<timekeepingntpl...@c3energy.com> wrote:
Hi all,
I just woke up to a 50 SECOND clock error. Prior to the error, with my
PC locked into the GPS and the internet servers noselected, here's what
my peerstats looked like. Baseline is the GPS. Colored lines are
internet servers.
http://dl.dropbox.com/u/9879631/drifting01-peerstats.20120312.jpg
Looking at this graph, I see that the nmea source was already difting
before the sudden jump. It lost 30ms wrt the other servers in the 20
hours beforehand. Then it went crazy for a while and jumped to 80 ms
ahead. I agree that this does seem to be that gps device. Which one is
it?
But that jump is 120ms not 50 sec.
I recently had a Garmin 18 go nuts-- giving massive amounts of noise.
That's very interesting. David Taylor also said he saw this NMEA
wandering effect on the Garmin. Did your Garmin recover? And, is it
based on a SIRF chipset?
In another thread, someone else with a BU-353 said he saw an "offset
storm" like the one in my graph.
Sincerely,
Ron
Here is what was showing on the Meinberg Time Server Monitor when I woke up:
http://dl.dropbox.com/u/9879631/drifting02a%20-%20insane.jpg
And the graph of the peerstats for that time:
http://dl.dropbox.com/u/9879631/drifting02b%20-%20peerstats%20insane.jpg
The clock error was REAL, as confirmed by my atomic wrist watch.
However, the loopstats graph for the same time period shows no problem
with the GPS:
http://dl.dropbox.com/u/9879631/drifting02c%20-%20gps%20NOT%20insane.jpg
So, I shut down NTPD and reset the time with a batch file that calls
ntpdate and querys the New York NIST server:
http://dl.dropbox.com/u/9879631/drifting02d%20-%20set%20with%20ntpdate.jpg
Here is the time server monitor shortly after NTPD restart:
http://dl.dropbox.com/u/9879631/drifting02e%20-%20shortly%20after%20ntpd%20restart.jpg
And after a 2nd restart:
http://dl.dropbox.com/u/9879631/drifting02f%20-%202nd%20ntpd%20restart%20after%20insane.jpg
And here are the current peerstats, which look normal. The offset to
the internet servers tends to drift and will eventually cross the zero
line and get positive.
http://dl.dropbox.com/u/9879631/drifting02g%20-%20peerstats%20after%20insane%20and%202nd%20reset.jpg
The GPS appears to have been stable all through this, and was never
powered off or unplugged. It looks like NTPD went crazy and reset my
clock for some reason.
It also reset all of the remote servers at the same time? Since it was
an offset of your system with respect to the remote systems.
Here are the peerstats and loopstats during the insane period.
http://dl.dropbox.com/u/9879631/loopstats.20120313-1-restart%20around%201350%20utc
http://dl.dropbox.com/u/9879631/peerstats.20120313-1-insane
Here is my current ntp.conf:
http://dl.dropbox.com/u/9879631/ntp.conf
My system is Windows 7, NTP 4.2.7p259, GPS GlobalSat BU-353 USB NMEA
only with GPGGA sentence at 57,600 baud.
If anyone can shed some light on what happened, please do. It's driving
me bonkers. I don't believe the GPS is at fault, and I suspect NTPD.
Again, the remote servers all agree. The GPS time does not (driving your
system time) .
Thanks in advance.
Sincerely,
Ron
--
(PS - If you email me and don't get a quick response, don't be concerned.
I get about 300 emails per day from alternate energy mailing lists and
such. I don't always see new messages very quickly. If you need a
reply and have not heard from me in 1 - 2 weeks, send your message again.)
Ron Frazier
timekeepingdude AT c3energy.com
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