[ntp:questions] Meinberg NTP monitor, silly question

unruh unruh at wormhole.physics.ubc.ca
Tue Dec 22 22:06:00 UTC 2009

On 2009-12-22, David Lord <snews at lordynet.org> wrote:
> Richard B. Gilbert wrote:
>> unruh wrote:
>>> On 2009-12-22, Richard B. Gilbert <rgilbert88 at comcast.net> wrote:
>>>> David J Taylor wrote:
>>>>> "Richard B. Gilbert" <> wrote in message 
>>>>> news:ZJydnVuvufm1Wa3WnZ2dnUVZ_h2dnZ2d at giganews.com...
> Yes, I've used chronyd along with ntpd for a while. I've moved
> desktops and notebooks to chronyd.
> What chronyd seems not to provide is peering ability with ntpd
> (or it may be I've never been able to get it working), and up
> to recently lacked any refclock support.

Not sure what "peering" ability means. It can certainly use ntpd as a
server source.  It now has refclock support (shm, socket) and you can
set up ntpd so that it feeds its refclock output to chrony via the
socket ( and via the hacked ntpd that M Lichvar has created which uses
ntpd purely to get the refclock times and feed it to chrony-- so you
have all of the refclock support that ntpd has.)

These are in 1.24-pre1 from chrony.tuxfamily.org

> For ntpd I've had problems with long periods to come into sync,
> temperature, system load or network disturbance causing
> instability. With older systems it was possible to reduce these
> effects by fiddling system clock frequency to within 10ppm or
> so, but with most recent software some systems where previously
> I had ntpd tamed are now back to being unstable due to self
> calibration putting them 50ppm or more out, but not consistent
> between reboots, (that isn't due to ntpd, just that it
> exacerbates the problems and I suspect this will also affect
> chronyd).

Yes, a real problem with Linux these days. Chrony takes about 15 min to
adjust to the new rate, rather than the 10 hours it takes ntpd. 

> David

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