[ntp:questions] flipping between stratum 1 clocks regularily

Jason Rabel jason at extremeoverclocking.com
Tue Feb 19 17:33:53 UTC 2008

You can try using the "prefer" flag (read the docs) to have it stick to one
of the servers.


> I've recently been provided with 4 "highly accurate" ntp servers that
> are using GPS as their primary synchronization source.  Well, 2 of the
> hosts are using GPS (stratum 1) and the other two are syncing to those
> (stratum 2).  I've been going around configuring all 4 hosts in my
> ntp.conf and am starting to notice that my machines are flipping back
> and forth between the two stratum 1s.  I don't think this is
> desirable.
> Some of the documentation from the clock vendors suggests that their
> clocks are "so accurate" that ntp has a hard time determining which is
> more so and this affect can occur.  I was thinking of dropping one of
> the ST1 clocks from the config and going with 1 ST1 and 2 ST2s....
> that seems more stable in a test.  I wanted to see if anyone else has
> dealt with something similar and how you fixed it.

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