From owner-freebsd-questions@FreeBSD.ORG Fri Dec 21 19:16:41 2007 Return-Path: Delivered-To: questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 6694F16A41B for ; Fri, 21 Dec 2007 19:16:41 +0000 (UTC) (envelope-from SRS0=04527191878c7d9dce7039eb1c1e2f91e0593f8b=556=es.net=webster@es.net) Received: from postal1.es.net (postal4.es.net [IPv6:2001:400:6000:1::66]) by mx1.freebsd.org (Postfix) with ESMTP id 70A0013C4D9 for ; Fri, 21 Dec 2007 19:16:40 +0000 (UTC) (envelope-from SRS0=04527191878c7d9dce7039eb1c1e2f91e0593f8b=556=es.net=webster@es.net) Received: from vortex.es.net (vortex.es.net [198.128.1.16]) by postal4.es.net (Postal Node 4) with ASMTP (SSL) id AFL38339; Fri, 21 Dec 2007 11:16:39 -0800 Date: Fri, 21 Dec 2007 11:16:38 -0800 From: John Webster To: Bill Moran Message-ID: <073F818C772E47BF16B6A94F@vortex.es.net> In-Reply-To: <20071221135129.ee20677e.wmoran@potentialtech.com> References: <20071218165521.GA37529@bewilderbeast.blackhelicopters.org> <343753.78466.qm@web44811.mail.sp1.yahoo.com> <20071221112303.19619c39.wmoran@potentialtech.com> <7BEE288E7C218E96DB9E8AA0@jw-laptop.dhcp.lbnl.us> <20071221132440.31ded74f.wmoran@potentialtech.com> <62F8888810A130657FBCAF47@vortex.es.net> <20071221135129.ee20677e.wmoran@potentialtech.com> X-Mailer: Mulberry/3.1.6 (Linux/x86) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline X-Sender-IP: 198.128.1.16 X-Sender-Domain: es.net X-Recipent: ; ; ; ; X-Sender: X-To_Name: Bill Moran X-To_Domain: potentialtech.com X-To: Bill Moran X-To_Email: wmoran@potentialtech.com X-To_Alias: wmoran Cc: questions@freebsd.org, "Michael W. Lucas" , shinny knight Subject: Re: timekeeping on jail servers X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: John Webster List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 21 Dec 2007 19:16:41 -0000 --On Friday, December 21, 2007 13:51:29 -0500 Bill Moran wrote: > In response to John Webster : >> > Not generally suitable for cron because it can take longer to slew >> > than it does for the next cron execution to occur, which would then >> > result in multiple ntpdate programs fighting each other (not sure >> > what the effect of this would be). >> >> If I were doing it I would write a script with locking in order >> to ensure multiple jobs don't fight. Simple. > > Umm .... > > At that point, why not just run ntpd? You've basically replaced it > with a script anyway. > My suggestions are based on the OP about ntpd binding to everything. > Besides, it's not that easy. As Chuck pointed out, ntpdate calls > adjtime() and exits, which means an adjustment might already be in > progress when you you call it again. I don't know if ntpdate checks > the return pointer from adjtime() to avoid multiple adjustment > requests. Just out of curiosity, why run it more that once a day? Or for that matter every couple of days?