From owner-freebsd-questions@FreeBSD.ORG Fri Dec 21 18:33:39 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 9264716A417 for ; Fri, 21 Dec 2007 18:33:39 +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 64BA413C458 for ; Fri, 21 Dec 2007 18:33:39 +0000 (UTC) (envelope-from cswiger@mac.com) Received: from relay11.apple.com (relay11.apple.com [17.128.113.48]) by mail-out4.apple.com (Postfix) with ESMTP id 5A35B1CACDEF; Fri, 21 Dec 2007 10:33:39 -0800 (PST) Received: from relay11.apple.com (unknown [127.0.0.1]) by relay11.apple.com (Symantec Mail Security) with ESMTP id 41B6A28082; Fri, 21 Dec 2007 10:33:39 -0800 (PST) X-AuditID: 11807130-a7e4abb000004fb9-d3-476c070369a5 Received: from cswiger1.apple.com (cswiger1.apple.com [17.214.13.96]) (using TLSv1 with cipher AES128-SHA (128/128 bits)) (No client certificate requested) by relay11.apple.com (Apple SCV relay) with ESMTP id 20E442804D; Fri, 21 Dec 2007 10:33:39 -0800 (PST) Message-Id: From: Chuck Swiger To: Bill Moran In-Reply-To: <20071221132440.31ded74f.wmoran@potentialtech.com> Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes Content-Transfer-Encoding: 7bit Mime-Version: 1.0 (Apple Message framework v915) Date: Fri, 21 Dec 2007 10:33:38 -0800 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> X-Mailer: Apple Mail (2.915) X-Brightmail-Tracker: AAAAAA== Cc: FreeBSD Questions Subject: Re: timekeeping on jail servers 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: Fri, 21 Dec 2007 18:33:39 -0000 On Dec 21, 2007, at 10:24 AM, Bill Moran wrote: >> ntpdate -B should slew the time slowly. (According to the manpage.) > > 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). ntpdate -B calls adjtime(2) and then exits, rather than the process staying around; calling it a second time is fine but it isn't especially useful to keep running ntpdate via cron. One should run ntpd instead unless the system in question is desperately short on memory and a ~1MB RSS process is a burden. > If you ask me, the -B option is available for people who want to > totally hose timekeeping on their system. Somewhat. :-) -- -Chuck