From owner-freebsd-questions@FreeBSD.ORG Thu May 15 22:36:02 2008 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 CEDD01065673 for ; Thu, 15 May 2008 22:36:02 +0000 (UTC) (envelope-from cswiger@mac.com) Received: from mail-out4.apple.com (mail-out4.apple.com [17.254.13.23]) by mx1.freebsd.org (Postfix) with ESMTP id B625B8FC2A for ; Thu, 15 May 2008 22:36:02 +0000 (UTC) (envelope-from cswiger@mac.com) Received: from relay12.apple.com (relay12.apple.com [17.128.113.53]) by mail-out4.apple.com (Postfix) with ESMTP id A93712D0CC73; Thu, 15 May 2008 15:36:02 -0700 (PDT) Received: from relay12.apple.com (unknown [127.0.0.1]) by relay12.apple.com (Symantec Mail Security) with ESMTP id 93FD7464003; Thu, 15 May 2008 15:36:02 -0700 (PDT) X-AuditID: 11807135-aa9bdbb000000d04-d1-482cbad263ed Received: from cswiger1.apple.com (cswiger1.apple.com [17.214.13.96]) by relay12.apple.com (Apple SCV relay) with ESMTP id 7571C420002; Thu, 15 May 2008 15:36:02 -0700 (PDT) Message-Id: <08073D5A-7E00-4BF3-BAC8-21088EB513D8@mac.com> From: Chuck Swiger To: Volker Jahns In-Reply-To: <20080515195302.GA13531@ikarus.thalreit> Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes Content-Transfer-Encoding: 7bit Mime-Version: 1.0 (Apple Message framework v919.2) Date: Thu, 15 May 2008 15:36:02 -0700 References: <20080515185758.GA12709@ikarus.thalreit> <597571FB-C72D-4603-B379-A59A435843BE@mac.com> <20080515195302.GA13531@ikarus.thalreit> X-Mailer: Apple Mail (2.919.2) X-Brightmail-Tracker: AAAAAA== Cc: freebsd-questions@freebsd.org Subject: Re: time drift 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: Thu, 15 May 2008 22:36:02 -0000 On May 15, 2008, at 12:53 PM, Volker Jahns wrote: >> While you should run ntpdate -b at system boot, running ntpdate >> periodically via cron is not the right thing to do-- you should run >> ntpd instead, and that will figure out the intrinsic correction your >> chosen system clock needs to keep better time via the ntp.drift file. > > Running ntpd on this system results in time drift of approx. 1-2 hrs > a day. That is not an acceptable option. Something's probably wrong with your hardware clock or there is something else going on, if it is really drifting at ~ 5% from real time. Sometimes replacing the battery on the motherboard fixes this. Does "vmstat -i" show exceptional interrupt load or anything like that? >> You should also take a look at the output of "sysctl >> kern.timecounter", and possibly switch to a different mechanism, if >> the existing choice doesn't work out well for your machine... > Thanks for the hint. Indeed, try using one of the other timesources and see whether that corrects the huge offsets you are reporting. -- -Chuck