> Date: Sunday, February 05, 2017 10:26:05 -0500 > From: Robert Moskowitz <rgm at htt-consult.com> > > I have read: > http://thegeekdiary.com/centos-rhel-7-chrony-vs-ntp-differences-bet > ween-ntpd-and-chronyd/ > > My server is up all the time and will serve time to internal > systems (via DHCP options). > > Caveat is that my server is an armv7 (Cubieboard2) which does not > have an RTC (no battery). So whenever the system boots, the time > is ZERO (Dec 31, 1969 or some such). > > Chrony fixes this really fast; shortly after boot the time is good. > Chrony CAN be configed as an internal time server. But chrony does > not seem to step the clock for any adjustments needed. It is more > important that this systems time be right all the time than to > avoid clock steps. > > This brings me back to NTP, which normally takes hours to bring the > time from ZERO to current, but keeps the time correct. > > So: > > Can Chrony check the time, say once a day? > > Or can NTP make a BIG time jump all at once (on system restart)? Where I have somewhat similar issues, I have historically used a crontab "@reboot" entry to call ntpdate which gets the clock set correctly. From there ntp keeps it in sync. This can now be accomplished with ntpd, and ntpdate is threatened with depreciation/retirement. See the top of the ntpdate man page for more details.