In article <[EMAIL PROTECTED]> [EMAIL PROTECTED] (Hal Murray) writes: > >>Well, I was mainly thinking of the case where you have orphan mode set >>up as a fallback to external servers - then the drift value that has >>been calculated while external servers were reachable is a good "quality >>indicator". But I assume the non-"masters" in an orphan-only setup >>calculate a drift relative to the "master" - in that case, if you're >>happy with the drift of the "master", you will be least unhappy if the >>host with the lowest drift relative to the departed "master" is chosen >>as the new "master". > >The value of drift doesn't have any correlation to goodness.
Well, in the case where you have a bunch of hosts synchronized to a server that only uses its local clock, it is obviously good if that server has a low drift relative to "real" time - both for keeping the time as close to the "real" time as possible, and for reducing the risk of the particular problem mentioned earlier in the thread, that the difference in drift between the server and some client exceeds 500 ppm. On the other hand, the method I suggested, looking at the calculated (whether based on "real" time or on previous orphan-"master" time) drift when making the choice of a new orphan-"master", can't actually work of course: If you have a calculated drift for server X, compensation for that drift will continue to be applied if server X is chosen as new "master", thus all servers are equally "good" in that case. The case where it *would* be useful to know the drift is in the initial selection of a "master" in a group that has never had the opportunity to calculate drift relative to "real" time (and hence the chosen "master"'s clock will be used without any drift compensation) - and in that case you by definition don't have any values to base the choice on. (Maybe that was what Steve was trying to tell me.:-) --Per Hedeland [EMAIL PROTECTED] _______________________________________________ questions mailing list [email protected] https://lists.ntp.isc.org/mailman/listinfo/questions
