Roger Oberholtzer wrote:
If NTP does not find an external server, it eventually falls back to localhost. localhost uses whatever the BIOS has for time.
Plus corrections for whatever drift ntp has calculated.
If your time looks correct in the absence of a ntp server, it is probably because of some mechanism other than ntp. Like the hwclock stuff openSUSE does at boot and shutdown. I think that is what maintains time between boots.
hwclock just sets the RTC - I don't know where it is today, but it used to be e.g. a little black clunky looking device, often by Dallas Semiconductor.
It requires that the time be correct when the system is shutdown. To whatever extent it is incorrect when it is shut down, it will be incorrect when it boots.
Plus or minus drift.
Given that ntp seems to only periodically re-check available servers, if the GPS is not on-line when it checks, it may be missed.
I'm not sure, but I suspect NTP check its servers and peers on every poll. When it has a stable signal from a higher-stratum server, it'll switch.
Having claimed all this, I realize that I may have a few points wrong. I can only say that I see on my laptop (on and off a lot - external time source only available after boot is long completed) the unexpected ntp behavior described by others. I have no investment in using chrony or ntp. I am only exploring options at this time.
And my real question about any possible side effects of not running hwclock at system shutdown remains unanswered.
The RTC won't be set to O/S time, that's all. I may not have understood all of your problem, but without a frequent connection to an accurate time-source, any system will have to rely on a local clock for periods of time. AFAICT, both chrony and ntp know how to determine the local oscillator drift and massage the clock such that the local clock remains fairly accurate. If you need a higher degree of accuracy without a more accurate external time source, you have to improve the local time source - temperature controlled xtal oscillator etc. -- Per Jessen, Zürich (21.2°C) -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org