Re: [chrony-users] Does Chronyd update the hardware clock?

[Joe M <joe9mail@xxxxxxxxx>]

Hello Miroslav,

> > I presume that the functionality described above has to do with
> > setting the "rtcfile" in chrony.conf. Instead of setting "rtcfile" if
> > "rtcsync" is used, then does chrony automatically update the hardware
> > clock?
> 
> With rtcsync, the kernel will write the system time to the RTC every
> 11 minutes. I think this is usually good enough unless the computer is
> down for long periods of time and the network is not available on start.
> 
> With rtcfile (which can't be used together with rtcsync) chronyd will
> track how much is the RTC off and how quickly it is gaining/losing time.
> This alone is not very useful. You will need to start chronyd with the -s
> option to use that information and set the system time from RTC on
> boot, or at least trim the RTC before shutdown with the trimrtc
> command. With the latest chrony prerelease you can also use the
> rtcautotrim option to keep the RTC close to the system time, similarly
> to rtcsync.

Thanks, makes sense. I will read up on rtcautotrim.

> > I tested this by changing my system clock and hwclock to -2 mins. With
> > "rtcsync" and starting the chronyd process, it set the system clock
> > and the hwclock to the correct time. I just want to confirm that it is
> > expected behaviour.
> 
> It is.
Thanks again,
Joe

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