[ntp:questions] Re: Sufficient # servers to sync to

Brian Utterback brian.utterback at sun.removeme.com
Thu Mar 17 17:59:29 UTC 2005

Richard B. Gilbert wrote:

> Take an extreme case:
> Server A says it's 11:53
> Server B says it's 11:55
> Server C says it's 23:52

To add to what Brad said, what you really have is the following
candidates for the time:

1. The interval 11:53-11:55
2. The interval 11:55-23:52
3. The interval 11:53-23:52

Let's see... number 1 has two servers on it, number 2 has
two servers, and number 3 has all three servers. So, with
three servers voting for number 3, I guess it is the winner.

This means that all three servers are allowed to proceed to
the next stage in the selection, so server C may still get the nod.

Just to clarify, the vote goes to the shortest interval that has
at least n/2 servers on it. So, if we add one more server right
around 11:5x, we see that this would then create a new interval
with three servers, not allowing server C. The original long
interval will have all four, but is trumped by the shorter one
with three, since 3 is still more than n/2 = 4/2 = 2 servers on


If you put a submarine in a blender...
Brian Utterback - OP/N1 RPE, Sun Microsystems, Inc.
Ph:877-259-7345, Em:brian.utterback-at-ess-you-enn-dot-kom

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