[ntp:questions] NTP makes a time jump

David Lord snews at lordynet.org
Mon Jul 8 14:11:03 UTC 2013

karpekin at gmail.com wrote:
> Hello,
> Thanks for the answers!
> The reason of such a configuration is simple. Our equipment is a mission-critical set of devices that shall be running without NTP server available. Some drift away from a true time is tolerable. However, all devices must be synched with each other, to a max of 50ms. That's why I have as a fallback - "if no NTP server available, give devices at least your wrong timestamp and get all synched with it". 
> The 3 sec drift I set just to emulate the behavior of our "floating NTP island" for example after 2 years of no upsync. And the fact the time made a jump as soon as true server appeared, makes all the devices to jump, but not at the same time due to polling rates, causing all the devices to loose synch for at least max polling time. The ideal behavior I would like to reach is that the server will start to correct the time, slowly coming to the "real" NTP time.
> Thanks in advance for your advises!
> Igor.


"tinker step 0" prevents step adjustments and disables kernel
time discipline.

Rather than that, I'd suggest a rubidium laser derived reference
clock source either as system clock or pps source for your main
server. If you can peer some of your devices this can reduce the
drift vs a single server.

Depending on ntpd version you might also use
tos  orphan 10
rather than the


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