Hi, Suppose I have a desire that chrony conditions my RTC, say because the device is rebooted daily, internet isn't always on and the "off" time might be significant and measured in days. Lets also assume that system is not shutdown cleanly most of the time (hey, lets just call it the home router...)
Now, what are the negative implications of running "trimrtc" on boot? The docs suggest that chrony internally updates itself to factor in the rtc change? We can assume that it happens before any iburst or other network connectivity is finished, so we aren't disturbing any in-progress computation? Additionally I'm naively assuming that the previously calculated drift rates for the RTC are preserved, so even if we immediately turn the machine off again, then when we turn on (some days later) it will apply a sensible offset to the previously updated RTC? Assuming the above then running trimrtc at chrony startup seems safe? As such could we please have an option to do this automatically? "trimrtconstart" or similar The logic is that modern kernels set the clock from the RTC for you and then on some machines I see a clock skew detected once chrony wakes up and computes a better time by incorporating the known offset. One solution would be to run chrony earlier in the boot (what does Redhat do?). My suggestion at least means that the next reboot might start closer to the correct time (clearly depends a lot on reboot frequency). (The point of this change is not about increasing accuracy, it's only about decreasing the gap between RTC and clock, mainly to decrease the opportunity for boot scripts to use the wrong one) A related question is then - given I want chrony to learn a reasonable estimate of RTC drift, plus I want to run trimrtc periodically, what is a sensible frequency to set cron to call trimrtc? Hourly, daily, weekly? What is the shortest sensible trim that will still lead to a moderate estimate of RTC drift being learned? Thanks Ed W --- To unsubscribe email chrony-dev-requ...@chrony.tuxfamily.org with "unsubscribe" in the subject. For help email chrony-dev-requ...@chrony.tuxfamily.org with "help" in the subject. Trouble? Email listmas...@chrony.tuxfamily.org.
