[ntp:questions] NTP servers redundancy

David Woolley david at ex.djwhome.demon.invalid
Wed Jan 20 22:07:52 UTC 2010

Brian Utterback wrote:

> You are incorrect. It is relevant. In practice, no two servers EVER
> have exactly the same time. And each time NTP decides to switch to the
> other server, it is also going to adjust the clock frequency to

The clock frequency is based on the combined offset, so, unless you are 
using prefer flags, it should not jump when the system peer changes.

> compensate for the perceived drift, even though the clock frequency
> may have already be correct.  It is thus likely for clock hopping to
> cause a feedback loop that will take the system clock outside of the
> interval between the two clocks. With the correct timing on the
> hopping, it can go very far outside the interval.

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