> On Thu, Nov 24, 2016 at 10:25:26AM +0100, Wielant, Ulrich wrote:
>> After chrony synchronized once to the PPS it never selects another time 
>> source although the PPS/GPS signal might disappear. This might be the case 
>> if gpsd is not running, the GPS is off or the GPS has no fix.
>>
>> MS Name/IP address         Stratum Poll Reach LastRx Last sample
>> ===============================================================================
>> #- GPS                           0   4     0   21m    +44ms[  +44ms] +/-  
>> 200ms
>> #* PPS                           0   4     0   21m  -1211ns[-2913ns] +/- 
>> 1634ns
>> ^- ntp03.cc-netzwerk.de          3   8   377    47  -1809us[-1809us] +/-   
>> 42ms
>> ^- ts1.sct.de                    2   8   377    55   -403us[ -403us] +/-   
>> 60ms
>> ^- news01.nierle.com             2   8   377   246  -1518us[-1518us] +/-   
>> 38ms
>> ^- xserv-01.tenretni.org         2   8   377    53  -4528us[-4528us] +/-   
>> 58ms
>>
>> What do I have to do so that chrony no longer synchronizes to the non 
>> available PPS/GPS source?
>
> Just wait a bit longer :). The PPS source was much better than the NTP 
> servers, so it may take couple hours before chronyd assumes the clock has 
> drifted so much that it should switch to the significantly worse NTP sources. 
> It's a feature, not a bug. If chronyd switched immediately to another source, 
> that would be bad for accuracy of the clock, e.g. when the GPS has a weak 
> signal and PPS stops for couple of minutes at a time.

Thanks!
Is there a parameter so that chrony switches faster although it is bad for 
accuracy?

>> I would also modify the stratum of the PPS/GPS source but this doesn't seem 
>> to be possible with refclock sources. Correct?

> Right, there is currently no option to set stratum for refclocks. It wouldn't 
> make much of a difference in the source selection anyway.

Is there an option so that common NTP servers are preferred and PPS/GPS is 
taken only if there is no other server? This might sound strange (it is ;-)) 
but this is a requirement for my current project. GPS/PPS should be used as 
fallback only.

Ulrich

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