> On Mon, Jul 18, 2011 at 6:31 PM, Theo de Raadt <dera...@cvs.openbsd.org>
> wrote:
> > There is ntp everywhere. Use:
> >
> > server myownmachine.mynetwork.xx
> > servers pool.ntp.org
>
> I often plug this laptop in to unknown stuff (or mirror/span ports or
> ethernet taps) and run tcpdump so I don't want to run any daemons that
> generate traffic. It's a little netbook and I use it for network
> troubleshooting only - it isn't a normal laptop setup. My main laptop
> does run ntpd all the time though.
Sorry; your usage case is not typical and you'll need to cope.
> I guess I will just use ntpd from now on and manually stop it if
> needed. Of course, with ntpd_flags="-s" in my rc.conf.local I won't
> be able to start it again without jumping the clock.
I suggest you don't start it with ntpd_flags=-s. ntpd converges fast
enough on a good machine, and your machine is not deviating very much
while it is off or suspended. Go measure some numbers.
> What do you think of making -s the default in /etc/rc.d/ntpd so it
> always syncs during boot but not any subsequent manual
> starts/restarts? Then one would just use ntpd_flags="" in
> rc.conf.local (or "-S" to disable the auto sync if desired). If ntpd
> crashed on a server the only way to safely start it again would be to
> reboot (or run ntpd directly but that negates the whole point of
> rc.d).
We are not going to make -s the default for a variety of reasons.
1 - it adds latency to the boot process.
2 - it is not neccessary. Try it. Unless you have spent a good amount
of time in ddb and then continued your machine, it will be very close.
3 - jumping time implies forward jumps primarily, but it also includes
backwards jumps. Backwards time jumps can have insane consequences.
Unless you have real measured evidence that prove you have case where
you NEED -s, you should not use it.
> ntpd -s does exactly the same thing. Clock jumps are fine during boot.
No, clock jumps are not good at all. Lacking evidence, I would argue
they are not even neccessary. Before the new rc subsystem, those
clock jumps were quite late in the boot process, too. Now ntpd is
started earlier. If the clock is off, we realy want slow shifts.
> Since rdate_flags was left in rc.conf, I thought the removal may have
> been an oversight.
Leaving it in rc.conf was an oversight. That has been fixed.
