From owner-freebsd-questions@FreeBSD.ORG Tue Apr 21 19:07:45 2009 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 3CBEA106566B for ; Tue, 21 Apr 2009 19:07:45 +0000 (UTC) (envelope-from cswiger@mac.com) Received: from asmtpout019.mac.com (asmtpout019.mac.com [17.148.16.94]) by mx1.freebsd.org (Postfix) with ESMTP id 25B0C8FC08 for ; Tue, 21 Apr 2009 19:07:45 +0000 (UTC) (envelope-from cswiger@mac.com) MIME-version: 1.0 Content-transfer-encoding: 7BIT Content-type: text/plain; charset=US-ASCII; format=flowed; delsp=yes Received: from cswiger1.apple.com ([17.227.140.124]) by asmtp019.mac.com (Sun Java(tm) System Messaging Server 6.3-8.01 (built Dec 16 2008; 32bit)) with ESMTPSA id <0KIG00GMYT4NDD60@asmtp019.mac.com> for freebsd-questions@freebsd.org; Tue, 21 Apr 2009 12:07:35 -0700 (PDT) Message-id: <09BFEE9D-B8CC-4B95-BF31-6C57D2866175@mac.com> From: Chuck Swiger To: Mel Flynn In-reply-to: <200904212057.59535.mel.flynn+fbsd.questions@mailing.thruhere.net> Date: Tue, 21 Apr 2009 12:07:34 -0700 References: <200904211106.01965.mel.flynn+fbsd.questions@mailing.thruhere.net> <200904212057.59535.mel.flynn+fbsd.questions@mailing.thruhere.net> X-Mailer: Apple Mail (2.930.3) Cc: freebsd-questions@freebsd.org Subject: Re: Preventing ntpd from adjusting time (backwards) X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 21 Apr 2009 19:07:45 -0000 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