From owner-freebsd-questions@FreeBSD.ORG Wed Aug 27 05:33:25 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 95D1D1065673 for ; Wed, 27 Aug 2008 05:33:25 +0000 (UTC) (envelope-from smithi@nimnet.asn.au) Received: from sola.nimnet.asn.au (paqi.nimnet.asn.au [220.233.188.227]) by mx1.freebsd.org (Postfix) with ESMTP id A92DC8FC1C for ; Wed, 27 Aug 2008 05:33:24 +0000 (UTC) (envelope-from smithi@nimnet.asn.au) Received: from localhost (localhost [127.0.0.1]) by sola.nimnet.asn.au (8.14.2/8.14.2) with ESMTP id m7R5XFJG055496; Wed, 27 Aug 2008 15:33:16 +1000 (EST) (envelope-from smithi@nimnet.asn.au) Date: Wed, 27 Aug 2008 15:33:14 +1000 (EST) From: Ian Smith To: Leslie Jensen In-Reply-To: <20080826201121.A75621065744@hub.freebsd.org> Message-ID: <20080827150359.D53360@sola.nimnet.asn.au> References: <20080826201121.A75621065744@hub.freebsd.org> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Cc: Andrew D , freebsd-questions@freebsd.org Subject: Re: Crontab and adjkerntz. 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: Wed, 27 Aug 2008 05:33:25 -0000 On Tue, 26 Aug 2008 16:05:13 +0200 Leslie Jensen wrote: > I have a machine that only runs during office hours. I've rescheduled > the periodic jobs in crontab so that they run when the machine is on. > > My question is can I reschedule the adjkerntz job as well, without > causing any problems? I'm concerned because the job is set to run 12 > times during night time, and I'm thinking that maybe it's a resource hog > and therefore it's not advisible to run it when one uses the machine? > > # Adjust the time zone if the CMOS clock keeps local time, as opposed to > # UTC time. See adjkerntz(8) for details. > 1,31 0-5 * * * root adjkerntz -a Just to add a bit to what Andrew and Matthew rightly said: sola# lastcomm -eE -f /var/account/acct.0 | grep adjkerntz adjkerntz - root __ 0.02 es Wed Aug 27 03:01 adjkerntz - root __ 0.00 es Wed Aug 27 02:31 adjkerntz - root __ 0.00 es Wed Aug 27 02:01 adjkerntz - root __ 0.00 es Wed Aug 27 01:31 adjkerntz - root __ 0.00 es Wed Aug 27 01:01 adjkerntz - root __ 0.00 es Wed Aug 27 00:31 adjkerntz - root __ 0.03 es Wed Aug 27 00:01 adjkerntz - root __ 0.00 es Tue Aug 26 05:31 adjkerntz - root __ 0.00 es Tue Aug 26 05:01 adjkerntz - root __ 0.00 es Tue Aug 26 04:31 adjkerntz - root __ 0.00 es Tue Aug 26 04:01 adjkerntz - root __ 0.00 es Tue Aug 26 03:31 After 27+ days uptime, not a full second of CPU time: 196 root 20 0 1316K 0K pause 0:00 0.00% 0.00% and that's on a 300MHz Celeron .. so no, it's certainly no resource hog! The 'adjkerntz -i' run at boot[1] should adjust for a TZ update occuring overnight, assuming CMOS has local time (ie /etc/wall_cmos_clock exists) [1] actually run when going to multi-user, so with CMOS set to local time, you should remember to run 'adjkerntz -i' when working in single user mode (eg make installworld) if you want correct file timestamps. cheers, Ian