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Re:
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From: |
Gary E. Miller |
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Subject: |
Re: |
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Date: |
Thu, 4 Jun 2020 12:33:10 -0700 |
Yo артур!
On Thu, 04 Jun 2020 21:49:00 +0300
артур хайруллин <ya_dinamovec@mail.ru> wrote:
> >> but i can’t understand. My logs have Thu, Jun 4 2020 14:00 —
> >> 14.30 events. But ntpd eats logs and output real time 19:10.
>
> > Good thing too. ntpd prevented you from setting a bad system time
> >from bad imput. How to break ntpd is better asked on an NTP list.
> >But for starters, by default ntpd wants 3 sources to agree before
> >changing the system time. Also by default nptd only makes large
> >changes to system time on startup. Both good things to prevent user
> >from shooting themselves in the foot.
>
> But i make this experiment because my system had time jumps in case
> of wrong ntpd input from gps receiver
Yup, so you said. But without proof, is just a theory. A good reason
to run the experiment you are running.
> I emulate this situation, i have logs with old data and when i try to
> write them ntp reacts not as i expect.
The number of people that know what ntpd will do is very small.
> Is it a good thing?
Is data good or bad? I think it is just data.
> Why ntpd
> reads old data from SHM but processes it like nothing have happened,
Because the data was rejected. I explained before: no cluster
confirmation, large changes prohibited after start.
> updates offset(offset is very small but difference between system
> time and server(SHM) time is large).
Without seeing your ntp logs, hard to say why.
> How is it possible?
Not only possible, but desinged that way, for good reason: to prevent what
you thought was happening.
> or i don’t
> understand the logic at all
Join the club. NTP is very complex. It tries hard to not be fooled and
do the right thing.
As I said before, this is now an NTP questions and you should ask on an NTP
list.
RGDS
GARY
---------------------------------------------------------------------------
Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
gem@rellim.com Tel:+1 541 382 8588
Veritas liberabit vos. -- Quid est veritas?
"If you can't measure it, you can't improve it." - Lord Kelvin
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