Unruh wrote: > "Richard B. Gilbert" <[EMAIL PROTECTED]> writes: > >> Unruh wrote: >>> "Richard B. Gilbert" <[EMAIL PROTECTED]> writes: >>> >>> >>>> There are other tools than NTPD. One called "chrony" MAY meet your >>>> needs, or may not. NTPD is very good at working over the Internet with >>>> its unpredictable queuing delays. Chrony, as I understand it, is not so >>>> good at working over the internet. >>> No idea where you get this from. chrony works over the internet at least as >>> well as does ntpd. Its philosophy of dealing with different delays is >>> different than ntp's( although it can be set up to be virtually identical) >>> >>> >>>> If you can't keep your machines up 24x7, chrony MAY be a better tool. >>>> It's possible that you will need something else entirely. >>> Possibly true. >>> >>> >>>> You may find that a hardware reference clock; e.g. a GPS timing >>>> receiver, will help. With a GPS timing receiver, you will not be >>>> dependent on the internet for time sources. NTPD will still need about >>>> thirty minutes to gain really tight synchronization. Once gained, >>>> synchronization should be stable as long as the machine is up. >>> Actually it is much worse than that. On my system, on bootup the clock >>> frequency can very by up to about 50PPM due to a Linux bug. In general it >>> takes ntp about 10 hours to regain tight synchronisation. (In that case it >>> is microsecond since it is synching to a GPS, but it is also on poll level >>> 4 so it has lots of data and should converge faster than some other system >>> on poll level 6-10). David Mills has always insisted that ntpd is designed >>> for stable long time operation, and rapidity of response is a distant 49th >>> or so in priority. >>> > >> My Solaris 8 SPARC system seems to be able to synch with the GPS >> receiver in about 30 minutes. I may reboot that system once a year > > IF the frequency after reboot is very close to the frequency before (<1PPM > say) and the clock has not drifter far out ( 1ms say) then sure. Otherwise > it is a disaster. > >> unless we have a power outrage that lasts longer than the UPS battery! >> Absent something like a power failure there's no real reason to reboot >> it at all. > > Well, no. Power supply intermittent failure can have you rebooting 10 times > a week. (Yes, that is experience talking-- three weeks ago) >
Your power quality seems to be a LOT worse than mine. It has been almost a year since the last time power went off here. A guy a couple of blocks from here trimmed the trees that were in contact with the power lines and that has made a HUGE difference. I have UPS for most of the machines in the house. They never notice the brownouts and most of the blackouts! _______________________________________________ questions mailing list [email protected] https://lists.ntp.org/mailman/listinfo/questions
