Re: [chrony-users] System Time Offset in Logs?

[Zack Shivers <zack@xxxxxxxxx>]

> Measurements contains the difference between the system time and the time
> obtained from the ntp packet, statistics contains the estimated offset as
> determined by the least squares fit on the last N measurements. That is maybe
> what you want.

Hmm, when I look at measurements, it does not match.

For the sake of testing, I manually offset the system time on the server:
timedatectl set-time <date-5min-in-past>

I quickly check 'chronyc tracking' on the client:
Reference ID    : C0A80002 (burrata-com-1)
Stratum         : 11
Ref time (UTC)  : Tue Sep 24 22:09:08 2019
System time     : 326.629364014 seconds fast of NTP time
Last offset     : +0.000008316 seconds
RMS offset      : 1.175688386 seconds
Frequency       : 30.445 ppm fast
Residual freq   : +8.221 ppm
Skew            : 237.633 ppm
Root delay      : 0.000233696 seconds
Root dispersion : 0.000234681 seconds
Update interval : 0.1 seconds
Leap status     : Normal

Now looking at the measurements log on the client, the number in the
'Offset' column of the measurements log briefly spikes to -3.27E+02
for 10 samples, then drops to roughly -2E-6. Meanwhile, even minutes
later, 'chronyc tracking' shows a 'System time` value in the hundreds
of seconds.

Why do these values not match all the time? If measurements logs the
difference between system time and the NTP server system time, why do
I not see large and slowly decreasing numbers in the measurements log?


On Tue, Sep 24, 2019 at 2:21 PM Bill Unruh <unruh@xxxxxxxxxxxxxx> wrote:
>
> On Tue, 24 Sep 2019, Zack Shivers wrote:
>
> > It appears that none of the logs contain the system time offset. Is there a way to enable logging this?
> > The field I'm interested in is the one given by 'chronyc tracking' as 'System time'.
>
> Which logs are you writing out?
>
> Measurements contains the difference between the system time and the time
> obtained from the ntp packet, statistics contains the estimated offset as
> determined by the least squares fit on the last N measurements. That is maybe
> what you want.
> >
> >
>
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