[ntp:questions] ntpd -gq VS ntpdate -B

RICCARDO castellani.riccardo at tiscali.it
Thu Apr 12 14:25:32 UTC 2007


On 11 Apr, 16:39, Tom Smith <s... at cag.zko.hp.com> wrote:
> "ntpdate -b" steps the time after doing a quick look at set of
> candidates you have specified on the command line. It is what
> is normally recommended for a boot sequence prior to starting ntpd.
>
> "ntpdate -B" slews the time, but is otherwise the same. Not
> usually recommended for a boot sequence because the initial
> time setting isn't complete when it exits.
>
> "ntpd -gq" uses all the convergence rules of the normal
> ntpd against a list of servers specified in a separate
> configuration file. After selecting a peer, it will either
> step OR slew the time, depending on the magnitude of
> the offset, and the time adjustment may or may not be
> complete when it exits. It is not equivalent to either
> "ntpdate -b" or "ntpdate -B".
>
> ntpdate takes a few milliseconds to run (dependent on
> network delays and timeouts) and sets the clock typically
> within a few milliseconds of "correct" with respect to
> the servers you have chosen to use. "ntpd -gq" takes a minimum
> of a few seconds to reach convergence and produces about the
> same practical level of accuracy. In steady state, ntpd,
> of course, is much more accurate and less disruptive than
> repeated use of ntpdate.
>
> -Tom
>
> castellani.ricca... at tiscali.it wrote:
> > I know ntpdate is deprecated but I'm interesting to know if they work
> > in the same way, is ntpdate behavior different in comparison to ntpd ?
>
> > ----Messaggio originale----
> > Da: s... at ntp.isc.org
> > Data: 11/04/2007 1.43
> > A: <questi... at lists.ntp.isc.org>
> > Ogg: Re: [ntp:questions] ntpd -gq VS ntpdate -B
>
> >>>> In article <1176216808.517213.274... at w1g2000hsg.googlegroups.com>,
> > "RICCARDO" <castellani.ricca... at tiscali.it> writes:
>
> > RICCARDO> If I use ntpd -gq in my client I should adjust time to
> > little
> > RICCARDO> steps using adjtime system call, but what's difference with
> > RICCARDO> "ntpdate -B" ?
>
> > ntpdate is being deprecated.
>
> > ntpd -gq will set the time and exit.  If the difference is less than
> > 128ms
> > the time will be slewed, if the difference is more the clock will be
> > stepped.
>
> > H
>
> > _______________________________________________
> > questions mailing list
> > questi... at lists.ntp.isc.org
> >https://lists.ntp.isc.org/mailman/listinfo/questions
>
> > Naviga e telefona senza limiti con Tiscali
> > Scopri le promozioni Tiscali adsl: navighi e telefoni senza canone Telecom
>
> >http://abbonati.tiscali.it/adsl/
>
> > _______________________________________________
> > questions mailing list
> > questi... at lists.ntp.isc.org
> >https://lists.ntp.isc.org/mailman/listinfo/questions


I want to use ntpd -qg, it could be right this ntp.conf for my Linux
client ?

restrict default ignore
restrict 127.0.0.1
restrict server A
restrict server B
server A
server B
driftfile /var/lib/ntp/drift
broadcastdelay  0.008

what means "the initial time setting isn't complete when it exits" ?




More information about the questions mailing list