| Re: [chrony-users] Fallback clock on event "Can't synchronise: no reachable sources" |
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Hi,
I finally could get the tracking logs from the computer with one of the
events in there, where the server is not reachable. Would be great if
someone could help me interpret them. What I find strange is that there
are large time intervals without an entry in the tracking.log file ...
what does that mean? Is there something that looks suspicious?
Thanks a lot, I appreciate the help!
Ulrich
tracking.log:
2014-02-17 11:09:38 192.168.0.30 14 -188.815 0.128 -2.652e-06
N 1 1.041e-05 -1.000e-06
2014-02-17 11:10:42 192.168.0.30 14 -188.825 0.105 -5.002e-06
N 1 9.495e-06 1.000e-06
==================================================================================================
Date (UTC) Time IP Address St Freq ppm Skew ppm Offset L
Co Offset sd Rem. corr.
==================================================================================================
2014-02-17 11:14:47 0.0.0.0 0 -188.825 0.105 0.000e+00
? 0 0.000e+00 0.000e+00
2014-02-17 11:20:06 192.168.0.30 14 -188.825 0.105 4.646e-01
N 1 8.165e-06 0.000e+00
2014-02-17 11:20:38 192.168.0.30 14 -188.825 0.105 -2.960e-02
N 1 7.342e-03 -4.700e-05
2014-02-17 11:21:10 192.168.0.30 14 -188.825 0.105 -1.061e-02
N 1 8.911e-03 3.000e-06
==================================================================================================
Date (UTC) Time IP Address St Freq ppm Skew ppm Offset L
Co Offset sd Rem. corr.
==================================================================================================
2014-02-17 11:22:27 0.0.0.0 0 -188.825 0.105 0.000e+00
? 0 0.000e+00 0.000e+00
2014-02-17 11:22:34 192.168.0.30 14 -188.825 0.105 -7.041e-03
N 1 7.408e-03 -1.356e-01
2014-02-17 11:22:36 192.168.0.30 14 -188.825 0.105 -1.281e-02
N 1 3.420e-03 -7.234e-02
2014-02-17 11:23:09 192.168.0.30 14 -188.825 0.105 -1.038e-02
N 1 1.155e-04 -4.000e-06
2014-02-17 11:23:41 192.168.0.30 14 -188.825 0.118 1.650e-04
N 1 1.582e-04 1.000e-06
2014-02-17 11:24:13 192.168.0.30 14 -188.825 0.141 4.837e-05
N 1 1.365e-04 -2.000e-06
2014-02-17 11:24:46 192.168.0.30 14 -188.824 0.191 6.054e-05
N 1 1.155e-04 -1.800e-05
2014-02-17 11:25:18 192.168.0.30 14 -188.820 0.296 4.109e-05
N 1 9.687e-05 -1.000e-05
2014-02-17 11:25:50 192.168.0.30 14 -188.792 0.584 7.567e-05
N 1 7.849e-05 -6.000e-06
==================================================================================================
Date (UTC) Time IP Address St Freq ppm Skew ppm Offset L
Co Offset sd Rem. corr.
==================================================================================================
2014-02-17 11:27:07 0.0.0.0 0 -188.825 0.105 0.000e+00
? 0 0.000e+00 0.000e+00
2014-02-17 12:43:35 192.168.0.30 14 -188.821 0.912 4.336e-01
N 1 1.704e-06 0.000e+00
2014-02-17 12:44:07 192.168.0.30 14 -188.821 0.912 -7.320e-04
N 1 8.288e-03 -4.400e-05
2014-02-17 12:44:40 192.168.0.30 14 -188.821 0.912 -7.830e-03
N 1 9.486e-03 5.310e-04
2014-02-17 12:45:12 192.168.0.30 14 -188.821 0.912 -4.389e-03
N 1 9.422e-03 1.060e-03
2014-02-17 12:45:45 192.168.0.30 14 -188.821 0.912 6.342e-04
N 1 8.040e-03 6.480e-04
2014-02-17 12:46:17 192.168.0.30 14 -188.821 0.912 3.129e-03
N 1 6.983e-03 1.300e-05
statistics.log:
2014-02-17 11:09:38 192.168.0.30 1.751e-05 -2.652e-06 1.041e-05
-4.848e-09 1.200e-07 4.5e-02 15 0 9
2014-02-17 11:10:42 192.168.0.30 1.708e-05 -5.002e-06 9.495e-06
-1.166e-08 9.607e-08 9.1e-02 16 0 9
==============================================================================================================
Date (UTC) Time IP Address Std dev'n Est offset Offset sd
Diff freq Est skew Stress Ns Bs Nr
==============================================================================================================
2014-02-17 11:20:06 192.168.0.30 1.246e-05 4.646e-01 8.165e-06
2.219e-06 1.972e-04 1.1e-03 3 0 3
2014-02-17 11:20:38 192.168.0.30 1.218e-02 -2.960e-02 7.342e-03
-4.316e-04 6.069e-03 2.2e+00 4 0 3
2014-02-17 11:21:10 192.168.0.30 1.131e-02 -1.061e-02 8.911e-03
-3.883e-04 1.876e-03 7.1e-03 5 0 4
==============================================================================================================
Date (UTC) Time IP Address Std dev'n Est offset Offset sd
Diff freq Est skew Stress Ns Bs Nr
==============================================================================================================
2014-02-17 11:22:34 192.168.0.30 1.128e-02 -7.035e-03 7.408e-03
-4.449e-03 3.047e+00 2.2e+00 3 0 3
2014-02-17 11:22:36 192.168.0.30 5.950e-03 -1.281e-02 3.420e-03
-5.375e-03 5.774e-02 3.0e-04 4 0 3
2014-02-17 11:23:09 192.168.0.30 2.581e-04 -1.038e-02 1.155e-04
-4.700e-04 2.011e-03 8.5e-02 5 0 3
2014-02-17 11:23:41 192.168.0.30 3.054e-04 1.650e-04 1.582e-04
4.645e-06 6.898e-05 2.4e-01 6 0 3
2014-02-17 11:24:13 192.168.0.30 2.378e-04 4.837e-05 1.365e-04
2.609e-06 2.497e-05 3.0e-02 7 0 4
2014-02-17 11:24:46 192.168.0.30 1.989e-04 6.054e-05 1.155e-04
2.262e-06 1.223e-05 1.4e-02 8 0 4
2014-02-17 11:25:18 192.168.0.30 1.728e-04 4.109e-05 9.687e-05
1.919e-06 7.081e-06 2.8e-02 9 0 4
2014-02-17 11:25:50 192.168.0.30 1.505e-04 7.567e-05 7.849e-05
2.041e-06 4.414e-06 1.8e-02 10 0 5
==============================================================================================================
Date (UTC) Time IP Address Std dev'n Est offset Offset sd
Diff freq Est skew Stress Ns Bs Nr
==============================================================================================================
2014-02-17 12:43:35 192.168.0.30 2.542e-06 4.336e-01 1.704e-06
1.581e-04 3.583e-05 7.9e-02 3 0 3
2014-02-17 12:44:07 192.168.0.30 8.349e-03 -7.320e-04 8.288e-03
7.286e-05 4.410e-03 2.4e+00 4 0 3
2014-02-17 12:44:40 192.168.0.30 9.411e-03 -7.830e-03 9.486e-03
-3.330e-05 1.436e-03 2.4e-02 5 0 3
2014-02-17 12:45:12 192.168.0.30 9.003e-03 -4.389e-03 9.422e-03
-5.436e-05 7.140e-04 1.5e-02 6 0 3
2014-02-17 12:45:45 192.168.0.30 8.527e-03 6.342e-04 8.040e-03
-3.774e-05 3.979e-04 2.3e-02 7 0 4
2014-02-17 12:46:17 192.168.0.30 8.356e-03 3.129e-03 6.983e-03
-1.324e-05 2.566e-04 6.2e-02 8 0 4
On 07.02.2014 15:37, Miroslav Lichvar wrote:
On Fri, Feb 07, 2014 at 02:10:32PM +0100, Ulrich Schwesinger wrote:
I have a system with a write protected system partition and an NTP
server running within a local network. Sporadically, chrony reports
the above mentioned error.
The error persists maybe within a time range of 20-30 seconds.
Within that time interval, the system time seems to diverge/drift by
a couple of 10 milliseconds, which seems unreasonable large for me.
How did you measure the error in that period?
(a) What is chrony exactly doing upon the event "Can't synchronise:
no reachable sources". It does not seem to keep the current system
time. Is it falling back on hardware clock maybe?
No, nothing with RTC. It should keep the system clock as it was set on
the last update unless chronyd is configured with the fallbackdrift
option.
(b) Or might something be wrong with the drift estimate, causing
this large divergence during the short time interval
Did it switch to another source before the "no reachable sources"
message? If there are multiple sources and the worst source becomes
unreachable as last, the clock will be set by the measurement from the
worst source, possibly introducing a large time or frequency error.
(c) Are there some files I could look at the trace back what's
happening within these time intervals?
The tracking log would be very helpful here. You can enable logging
in chrony.conf like this:
logdir /var/log/chrony
log measurements statistics tracking
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