On Sat, Feb 11, 2012 at 19:02, unruh <[email protected]> wrote: > On 2012-02-11, Dave Hart <[email protected]> wrote: >> On Sat, Feb 11, 2012 at 01:03, unruh <[email protected]> wrote: >>> On 2012-02-09, bombjack <[email protected]> wrote: >>>> What happens if I change the time on the server, lets say 5 years >>>> forward? Will the client sync to the server? and If so, how? big leap? >>>> small steps? Will the flag "-g" affect how the client reacts to this >>>> changes? >>> >>> No. If ntp finds the time out by >128ms, it steps the clock. If it finds >>> it out by 1000(?) sec it says "Something is horribly wrong here" and >>> abandons ship. (ntpd exits). >> >> Don't let facts get in the way of your recollections, I suppose. >> Quoting myself from this very thread: "-g allows a single step >> exceeding the panic threshold, not necessarily at startup." The panic >> threshold defaults to 1000 s. But don't take my word for it -- see >> the docs. > > ??? > a) that -g is typically used at startup and was introduced in order > to handle wildly out of sync clocks at starup. I suspect that the fact > that -g will also works if startup has been OK, but 17 days into running > it suddenly finds the clock out by 5 days is a bug in the implimentation > of -g.
I discovered today while looking at another issue that the ntpd -g explanation in ntpd.html and ntpd --help are both subtly wrong, and have been since -g was introduced in the earliest ntpd 4.x releases. As one might hope from a practical point of view, -g will not allow a panic-exceeding step except the first sync. The docs make no mention of first sync or startup or anything similar. > And my recollection seems to have been dead on. Yes, indeed. When I wrote the above, I assumed the docs correctly described the code's behavior and didn't verify by testing or code inspection. Cheers, Dave Hart _______________________________________________ questions mailing list [email protected] http://lists.ntp.org/listinfo/questions
