[ntp:questions] Does NTP cause an abrupt/sudden change in an orphan's system time?

Steve Kostecke kostecke at ntp.org
Wed Aug 8 14:42:50 UTC 2012

On 2012-08-08, Arpith Nayak <arpithnayak at gmail.com> wrote:

> I have a server that is in the orphan mode i.e. it was not connected to the
> internet (and thus the various public NTP servers) when I booted it up. Now
> if I install ntpd oin this server and run it, will the first instance of
> ntpd cause a sudden change in the system time as well as timestamps or does
> NTP cause a slow gradual change so that it syncs up with the public server
> over a period of time?

What will happen when ntpd is started has been discussed elsewhere in
this thread.

It should be noted that at the maximum slew rate of 500ppm ntpd can only
adjust the clock by 43.2 seconds per day (1.8 seconds per hour).

If the RTC is one minute off at boot time it will take more than a day
to amortize the error unless you allow ntpd to step the clock.

Steve Kostecke <kostecke at ntp.org>
NTP Public Services Project - http://support.ntp.org/

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