[ntp:questions] NTPD can take 10 hours to achieve stability
cswiger at mac.com
Mon Apr 18 23:25:48 UTC 2011
On Apr 18, 2011, at 2:54 PM, C BlacK wrote:
> Thanks for all the great answers. Now for a harder question, how does the accuracy of the local clock source affect the accuracy of ntpd.
Normally, except for stratum-1 NTP servers which are specifically configured to use a high-quality local timesource (ie, GPS, ACTS, WWV, atomic clocks, etc), the local clock isn't used at all. For stratum-2 and higher timeservers, ntpd will pick the most accurate timeserver based upon a selection algorithm, and discipline the kernel clock against that as the reference.
On many platforms, the kernel clock will periodically be written out to the system RTC (aka TOD/TOY clock) used to keep time when the system is powered off.
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