Re: [chrony-dev] Question / Feature suggestion - trimrtc on start?

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On Mon, 25 Jul 2011, Miroslav Lichvar wrote:

On Fri, Jul 22, 2011 at 04:40:58PM +0100, Ed W wrote:
Wouldn't it be better to make the step as early in the boot as
possible and not care about its size?

Definitely.  Actually I can easily adjust my boot scripts to run chrony
instead of hwclock - works well.  The disadvantages are that I need to
be careful about offline because I'm starting chrony before networking
(or investigate your most recent updates which I think allow this to
work ok?).

The recent changes are only about DNS. Unless you are using the
auto_offline flag, it should be safe to start chronyd before
networking. The Fedora chronyd service file specifies syslog as the
only dependency. If you don't mind losing some log messages on start,
you can start chrony even before that.

However, yes, I intend to use chrony instead of hwclock (I don't see
anyone needs hwclock now - kernel does --rtctosys itself and I think
many distros don't call --systortc, so hwclock is mostly redundant?)

Here, hwclock is still called on boot with the --systz option, to
reset the clock according to the current timezone (not needed if RTC
keeps time in UTC?). And it's also called on shutdown with --systohc.
If you don't have a shutdown, you could call it from cron, or after
some fixed time after chrony has synchronized the system clock.

That of course makes the chrony rtc code pretty useless, since the rtc has
been changed behind chrony's back and it has no idea that that has happened. It is of course one possible way to go and just disable the rtc in chrony. As I said, because of the heat sensitivity of the rtc, it is not clear exactly
how useful the chrony rtc code is. It spends much effort to very accurately
measure the rtc drift, but at the wrong temperature(s)




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