Re: [chrony-users] Can chrony correct very wrong RTC?

[Bill Unruh <unruh@xxxxxxxxxxxxxx>]

William G. Unruh __| Canadian Institute for|____ Tel: +1(604)822-3273
Physics&Astronomy _|___ Advanced Research _|____ Fax: +1(604)822-5324
UBC, Vancouver,BC _|_ Program in Cosmology |____ unruh@xxxxxxxxxxxxxx
Canada V6T 1Z1 ____|____ and Gravity ______|_ www.theory.physics.ubc.ca/

On Thu, 18 Oct 2018, Miroslav Lichvar wrote:

> On Thu, Oct 18, 2018 at 01:25:58PM +0200, Leo von Klenze wrote:
> > 1) on boot I set the Sysclock from the RTC via hwclock. hwclocks uses
> > the drift from /etc/adjtime
> > 2) afterwards chrony is started and I configured chrony to synchronize
> > the RTC on runtime
>
> rtcsync or rtcfile+rtcautotrim?
>
> > 3) on shutdown I ensure that the RTC is set to the Sysclock one last
> > time via hwclock
>
> It's not very clear to me how this works :). I think hwclock has the
> same requirement as chrony, that it has to be the only program
> adjusting the clock, otherwise the measured drift will be incorrect. I
> guess switching between them is possible, but when one adjusts the
> RTC, I think the drift file of the other one needs to be updated.

I think what he is doing is to measure the drift of the rtc when the computer
if off once by hand. He then enters that drift rate by hand into the adjtime
file on each shutdown, and does not allow hwclock to set it.


> --
> Miroslav Lichvar
>
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