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

David Woolley david at ex.djwhome.demon.invalid
Wed Aug 8 20:02:34 UTC 2012

Harlan Stenn wrote:

> If you override this in the ntp.conf file (or via a startup option) it
> will slew the time gradually, but realize it may take a *very* long time
> to get the clock right.  This type of change is applied at 500ppm, so a
> change of 1 second will be applied over 2000 seconds.

Also, if you set it to a relatively large value, ntpd will run in a 
degraded mode in which it slews the kernel time at + or - 500ppm, for 
part of each second (the user space time discipline).  If you want the 
timing adjusted on every clock tick, and accurately interpolated between 
them, you need to use the kernel time discipline, which this will disable.

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