dual-boot time issue

Colin Watson cjwatson at ubuntu.com
Tue Jun 12 19:11:08 UTC 2018

On Tue, Jun 12, 2018 at 01:34:29PM +0000, J.Witvliet at mindef.nl wrote:
> Option B) seems nice, but when using Kerberos, you need a steady and
> reliable time source.

As far as I can see, option B doesn't affect the maintenance of the
system clock while your system is running, and therefore it doesn't
impair your ability to have a steady and reliable time source.  It
simply configures the system to use an offset when writing to the
hardware clock at shutdown, and it doesn't stop you using NTP.

As I said in my previous message, you should leave out the
"--adjust-system-clock" option, since you don't want to resynchronise
your system clock from the hardware clock when you make this
configuration change.  That option is mainly intended for use in
environments where you have some reason to believe that the hardware
clock is likely to be more reliable than the system clock, which isn't
your case.

> So during shutdown I think the system should either:
> - Not write to the hwclock at all, or,
> - write the converted UTC-2-LTC (to keep the win-users happy)

"timedatectl set-local-rtc 1" configures the system to do the second of
those.  (Its main technical effect is to write appropriate configuration
to /etc/adjtime.)

It is possible I'm missing something, for example that there's some bug
that makes this not work properly, but at the moment it sounds as though
you're misunderstanding what "timedatectl set-local-rtc 1" does.

Colin Watson                                       [cjwatson at ubuntu.com]

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