| Re: [chrony-users] How to avoid oversteering |
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> chronyd should not be doing that. It has a very efficient way of determining
> what the correct rate should be, and uses an extra drift to drive the
> offset to zero.
>
> Is this on real hardware on a virtual machine? Chrony should not be run on
> virtual machines, because the timing on those is a mess. Their internal
> clocks are not regular.
thanks for your fast answer!
It is definitely NOTt a VM, but an ARM board (similar to BeagleBones black)
> Alternatively it could be a severe hardware issue
the system clock runs fine if left alone!! It drifts a few seconds per day, but
that's it.
Chrony changes the clock frequency enormously when it starts "correcting"
it... I can see that comparing system-clock and RTC times both with and
without chrony.
> or you could be running the system on a tickless clock.
That is a good hint! that is a kernel config option right?
> On Mon, 5 Feb 2018, Ariel Garcia wrote:
> > Hello,
> >
> > i am trying to get Chrony 3.2 running without stepping the clock, but i
> > find that it oversteers by a huge amount. I observe that it starts
> > driving
> > the system clock to the right value, but then moves it more that the
> > initial offset in the opposite direction, and starts "oscillating".
> >
> > I rebooted to make sure the system clock runs at the "default" speed
> > initially, having previously set the RTC ~10s off from the correct time
> >
> > for testing. After chrony started it reported:
> > System time : 10.891304016 seconds slow of NTP time
> >
> > After ~ 10 minutes running it was already:
> > System time : 2.529696226 seconds slow of NTP time
> >
> > but then after ~20 minutes it was already in the opposite direction:
> > System time : 12.160170555 seconds fast of NTP time
> >
> > After one hour running it is worse than at the beginning:
> > System time : 16.009445190 seconds slow of NTP time
> >
> > What am i doing wrong, am i having the wrong expectation, or could
> > it be a hardware or a configuration issue?
> > (the drift values shown above are consistent with the device's RTC
> > --which is not being adjusted-- and an external PC)
> >
> > I've tried to collect all details below,
> > thanks in advance for any hints/help!!
> > Ariel
> >
> >
> > ================================================================
> > Running on a BeagleBone black-similar board, with an AM335X CPU.
> >
> > My configuration was chosen as simple as possible to start:
> > --------------------------------
> > pool de.pool.ntp.org minpoll 4
> > makestep 3600 3
> > logchange 0.05
> > cmdallow 127.0.0.1
> > bindcmdaddress /run/chrony/chronyd.sock
> > pidfile /run/chrony/chronyd.pid
> > -------------------------------
> >
> > Of course i made sure there is no other NTP daemon running.
> > These are all running processes (only deleted my open ssh connections)
> > --------------------------------
> >
> > 1 ? Ss 0:10 /sbin/init
> >
> > 978 ? Ss 0:03 /usr/sbin/rngd -f
> > 985 ? Ss 0:04 /lib/systemd/systemd-journald
> >
> > 1773 ? Ss 0:00 /lib/systemd/systemd-udevd
> > 1805 ttyO0 Ss+ 0:00 /sbin/agetty --keep-baud 115200 38400 9600 ttyO0
> > vt220 1812 ? Ss 0:00 /usr/bin/dbus-daemon --system
> > --address=systemd: --nofork --nopidfile --systemd-activation 1813 ?
> > Ss 0:00 /usr/sbin/crond -b
> > 1827 ? Ss 0:00 /lib/systemd/systemd-networkd
> > 1834 ? Ss 0:00 /lib/systemd/systemd-resolved
> > 15344 ? S 0:00 /usr/sbin/chronyd -4 -f /etc/chrony/chrony.conf
> > --------------------------------
> >
> > The servers are reachable and seem ok:
> > --------------------------------
> > $ chronyc -n sources
> > 210 Number of sources = 4
> > MS Name/IP address Stratum Poll Reach LastRx Last sample
> > ==========================================================================
> > ===== ^- 172.104.239.150 2 4 377 3 -1158ms[-1158ms]
> > +/- 58ms ^- 138.201.135.108 2 4 377 4
> > -1057ms[-1057ms] +/- 47ms ^* 195.34.187.132 2 4 377
> > 14 +17ms[-1527ms] +/- 28ms ^- 5.9.78.71 2 4
> > 377 13 -142ms[ -142ms] +/- 50ms
> >
> > $ chronyc -n sourcestats
> > 210 Number of sources = 4
> > Name/IP Address NP NR Span Frequency Freq Skew Offset Std
> > Dev
> > =========================================================================
> > ===== 172.104.239.150 6 3 75 -103422 1668.695
> > -1033ms 14ms 138.201.135.108 6 3 75 -103305
> > 1165.815 -1020ms 11ms 195.34.187.132 6 3 75
> > -103052 2391.831 -1021ms 15ms 5.9.78.71 6 3
> > 75 -102973 2085.425 -1017ms 14ms
> > --------------------------------
> >
> > The logs show
> > ---------------------------------
> > Feb 05 17:18:22 BBx systemd[1]: Starting NTP client/server...
> > Feb 05 17:18:22 BBx chronyd[15344]: chronyd version 3.2 starting (+CMDMON
> > +NTP +REFCLOCK +RTC +PRIVDROP -SCFILTER -SECHASH -SIGND +ASYNCDNS +IPV6
> > -DEBUG) Feb 05 17:18:22 BBx chronyd[15344]: Initial frequency 42.124 ppm
> > Feb 05 17:18:22 BBx systemd[1]: Started NTP client/server.
> > Feb 05 17:18:55 BBx chronyd[15344]: Selected source 129.70.132.35
> > Feb 05 17:18:56 BBx chronyd[15344]: System clock wrong by 11.087803
> > seconds, adjustment started Feb 05 17:19:11 BBx chronyd[15344]: Can't
> > synchronise: no majority Feb 05 17:19:12 BBx chronyd[15344]: Selected
> > source 129.70.132.35
> > Feb 05 17:19:12 BBx chronyd[15344]: System clock wrong by 1.096591
> > seconds, adjustment started Feb 05 17:19:27 BBx chronyd[15344]: Selected
> > source 138.201.135.108 Feb 05 17:19:27 BBx chronyd[15344]: System clock
> > wrong by 0.943644 seconds, adjustment started Feb 05 17:19:43 BBx
> > chronyd[15344]: System clock wrong by 1.241887 seconds, adjustment
> > started ...
> > (lots or similar lines, but always the system clock is reported to be
> > wrong
> >
> > by +2 to -2 seconds, never by the amount shown by "chronyc tracking")
> >
> > ...
> > ---------------------------------
> >
> > The tracking data at different times:
> > ---------------------------------
> > $ chronyc tracking
> > Reference ID : 81468423 (stratum2-2.NTP.TechFak.NET)
> > Stratum : 3
> > Ref time (UTC) : Mon Feb 05 17:19:05 2018
> > System time : 10.891304016 seconds slow of NTP time
> > Last offset : -11.087802887 seconds
> > RMS offset : 11.087802887 seconds
> > Frequency : 42.124 ppm fast
> > Residual freq : +1.113 ppm
> > Skew : 1000000.000 ppm
> > Root delay : 0.037714522 seconds
> > Root dispersion : 3.768865824 seconds
> > Update interval : 0.0 seconds
> > Leap status : Normal
> > ---------------------------------
> > $ chronyc tracking
> > Reference ID : 8AC9876C (srv23.globale-gruppe.com)
> > Stratum : 3
> > Ref time (UTC) : Mon Feb 05 17:19:37 2018
> > System time : 9.804729462 seconds slow of NTP time
> > Last offset : -0.943643808 seconds
> > RMS offset : 0.943643808 seconds
> > Frequency : 42.124 ppm fast
> > Residual freq : -41046.902 ppm
> > Skew : 1000000.000 ppm
> > Root delay : 0.033498995 seconds
> > Root dispersion : 12.330061913 seconds
> > Update interval : 14.3 seconds
> > Leap status : Normal
> > ---------------------------------
> > $ chronyc tracking
> > Reference ID : 81468423 (stratum2-2.NTP.TechFak.NET)
> > Stratum : 3
> > Ref time (UTC) : Mon Feb 05 17:24:13 2018
> > System time : 9.454131126 seconds slow of NTP time
> > Last offset : +0.030433958 seconds
> > RMS offset : 0.640062451 seconds
> > Frequency : 90705.453 ppm slow
> > Residual freq : +86.611 ppm
> > Skew : 1054.889 ppm
> > Root delay : 0.035278354 seconds
> > Root dispersion : 0.017751774 seconds
> > Update interval : 16.1 seconds
> > Leap status : Normal
> > ---------------------------------
> > $ chronyc tracking
> > Reference ID : 81468423 (stratum2-2.NTP.TechFak.NET)
> > Stratum : 3
> > Ref time (UTC) : Mon Feb 05 17:31:07 2018
> > System time : 2.529696226 seconds slow of NTP time
> > Last offset : +0.029113885 seconds
> > RMS offset : 0.166937038 seconds
> > Frequency : 77410.445 ppm slow
> > Residual freq : +1074.334 ppm
> > Skew : 1991.644 ppm
> > Root delay : 0.035502460 seconds
> > Root dispersion : 0.027657172 seconds
> > Update interval : 15.8 seconds
> > Leap status : Normal
> > ---------------------------------
> > $ chronyc tracking
> > Reference ID : 8AC9876C (srv23.globale-gruppe.com)
> > Stratum : 3
> > Ref time (UTC) : Mon Feb 05 17:37:24 2018
> > System time : 6.902931690 seconds fast of NTP time
> > Last offset : +0.189766780 seconds
> > RMS offset : 1.233845592 seconds
> > Frequency : 108520.094 ppm fast
> > Residual freq : +12504.339 ppm
> > Skew : 30318.885 ppm
> > Root delay : 0.034667145 seconds
> > Root dispersion : 0.311530590 seconds
> > Update interval : 16.1 seconds
> > Leap status : Normal
> > ---------------------------------
> > $ chronyc tracking
> > Reference ID : 81468423 (stratum2-2.NTP.TechFak.NET)
> > Stratum : 3
> > Ref time (UTC) : Mon Feb 05 17:45:10 2018
> > System time : 13.315183640 seconds fast of NTP time
> > Last offset : -0.028802348 seconds
> > RMS offset : 0.300014675 seconds
> > Frequency : 106800.570 ppm fast
> > Residual freq : -74.106 ppm
> > Skew : 1022.886 ppm
> > Root delay : 0.034821544 seconds
> > Root dispersion : 0.017649684 seconds
> > Update interval : 16.2 seconds
> > Leap status : Normal
> > ---------------------------------
> > $ chronyc tracking
> > Reference ID : C322BB84 (powered.by.inet.de)
> > Stratum : 3
> > Ref time (UTC) : Mon Feb 05 18:06:29 2018
> > System time : 4.486146450 seconds slow of NTP time
> > Last offset : -0.437962651 seconds
> > RMS offset : 1.165199637 seconds
> > Frequency : 19659.746 ppm slow
> > Residual freq : -14884.478 ppm
> > Skew : 39623.336 ppm
> > Root delay : 0.025750067 seconds
> > Root dispersion : 0.237240255 seconds
> > Update interval : 3.7 seconds
> > Leap status : Normal
> > ---------------------------------
> > $ chronyc tracking
> > Reference ID : C322BB84 (powered.by.inet.de)
> > Stratum : 3
> > Ref time (UTC) : Mon Feb 05 18:19:55 2018
> > System time : 16.009445190 seconds slow of NTP time
> > Last offset : +0.026499212 seconds
> > RMS offset : 0.694284379 seconds
> > Frequency : 102772.656 ppm slow
> > Residual freq : +110.795 ppm
> > Skew : 1070.995 ppm
> > Root delay : 0.027395297 seconds
> > Root dispersion : 0.030097129 seconds
> > Update interval : 16.3 seconds
> > Leap status : Normal
> > ---------------------------------
> > $ chronyc tracking
> > Reference ID : AC68EF96 (watch.no-such-agency.net)
> > Stratum : 3
> > Ref time (UTC) : Mon Feb 05 18:52:14 2018
> > System time : 17.909534454 seconds fast of NTP time
> > Last offset : -0.021534055 seconds
> > RMS offset : 0.502140403 seconds
> > Frequency : 106267.859 ppm fast
> > Residual freq : -85.290 ppm
> > Skew : 1018.805 ppm
> > Root delay : 0.025392590 seconds
> > Root dispersion : 0.026234277 seconds
> > Update interval : 13.1 seconds
> > Leap status : Normal
> > ---------------------------------
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