[ntp:questions] Re: ntpd, boot time, and hot plugging

brad at shub-internet.org brad at shub-internet.org
Tue Feb 15 09:41:13 UTC 2005


"David L. Mills" <mills at udel.edu> wrote:

> Let me be sure this is your intent. Your minclock 4 says you must have
> at least 4 severs pass the maxdist threshold on the way down before
> setting the clock.

That's basically what I had understood.

>                           Against my better judgement the default
> minclock is 1, so ordinarily the clock is set by the first server found,
> and it might be a falseticker. I am happier with 4, because that's the
> Byzantine minimum that reliably kicks out a single ralseticker.

Which was the recommendation of your message in
<http://lists.ntp.isc.org/pipermail/questions/2003-September/000737.html>.

>                                               Your
> minsane 4 requires the clustering algorithm to stop tossing out outlyers
> when 4 remain. Also good Byzantine. But, if you did that, it would be a
> good idea to use a couple more servers, say a total of 6, so the
> clusting algorithm could improve the quality. However, with minclock 4,
> if for some reason less than that number of servers were actually
> available, the clock would never be set.

I am currently using more than six upstream servers.  Actually, I'm
currently using fourteen, and I should kick that down quite a bit, so as to
reduce my use of the pool.ntp.org servers.

> Is that what you had in mind? I have no problem with it, but I do want
> to make sure the model is clearly understood.

Yup, that was what I wanted.  However, based on your comments here, I
should update the page at
<https://ntp.isc.org/bin/view/Support/StartingNTP4#Section_6.1.4.3.> to
include the appropriate caveats.

Thanks!

-- 
Brad Knowles, <brad at stop.mail-abuse.org>

"They that can give up essential liberty to obtain a little temporary
safety deserve neither liberty nor safety."
    -Benjamin Franklin, Historical Review of Pennsylvania.

  SAGE member since 1995.  See <http://www.sage.org/> for more info.



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