Date: Tue, 21 Apr 2009 12:07:34 -0700 From: Chuck Swiger <cswiger@mac.com> To: Mel Flynn <mel.flynn+fbsd.questions@mailing.thruhere.net> Cc: freebsd-questions@freebsd.org Subject: Re: Preventing ntpd from adjusting time (backwards) Message-ID: <09BFEE9D-B8CC-4B95-BF31-6C57D2866175@mac.com> In-Reply-To: <200904212057.59535.mel.flynn%2Bfbsd.questions@mailing.thruhere.net> References: <200904211106.01965.mel.flynn%2Bfbsd.questions@mailing.thruhere.net> <C397BD04-8E91-4849-BB8F-A2034F10C18E@mac.com> <200904212057.59535.mel.flynn%2Bfbsd.questions@mailing.thruhere.net>
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On Apr 21, 2009, at 11:57 AM, Mel Flynn wrote: [ ... -x option... ] > Hmm, that might work. Thanks! Sure. >> It should be surprising that your clock would jump by 6 seconds. Do >> you have adequate upstream timesources (ie, at least 4) configured, >> is >> your local HW clock busted somehow, or are you doing something odd >> with power-savings mode or running in a VM or something...? > > One timesource, shared on local network, this machine is a client of > the > gateway, which uses only one source (ntp.alaska.edu, which is > geographically > 10 minutes by car but thanks to Alaska bad peering, we go through > Seattle > anyway). I checked the logs, that machine didn't step at all that > day (or any > other day, as far as my logs go). It always happens after reboot, as > Matthew > indicated. No VM, no power-savings. The only odd things are > Hyperthreading and > the reboot. OK, a step upon boot is not unusual-- some machines have poor timekeeping with the internal BIOS/battery-backed clock used when the system is off. Note that NTP falseticker detection really wants to have at least 4 timesources available for the algorithm it uses to detect whether an NTP source is behaving poorly. Try contacting your ISP for nearby NTP sources, or try adding 0.us.pool.ntp.org, 1.us..., & 2.us... to your config; the NTP pool nameservers use a geolocation mechanism to some extent to try and return NTP servers which are close. Regards, -- -Chuck
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