After PTP becomes unavaillable, chrony still selects it for a time period :
Reachability is not a requirement for selection. An unreachable source
can still be selected if its newest sample is not older than the oldest
sample from reachable sources.
This period is defined by the number of samples and the polling period and is, by default, highly variable (up to 10*1024s=~3h).
Set min/max for poll and sample for make this period more predictable:
poll = 6 => 2^6=64 seconds poll periode
sample = 10
So, the PTP->NTP fallback time around 11 minutes (10*64s)
After PTP becomes unavaillable, chrony still selects it for a time period :
This period is defined by the number of samples and the polling period and is, by default, highly variable (up to 10*1024s=~3h).
Set min/max for poll and sample for make this period more predictable:
So, the PTP->NTP fallback time around 11 minutes (10*64s)
Backported from debiancentos branch