From owner-freebsd-hackers@FreeBSD.ORG Sun Mar 8 12:36:18 2009 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 93D511065675 for ; Sun, 8 Mar 2009 12:36:18 +0000 (UTC) (envelope-from ticso@cicely7.cicely.de) Received: from raven.bwct.de (raven.bwct.de [85.159.14.73]) by mx1.freebsd.org (Postfix) with ESMTP id 1838B8FC18 for ; Sun, 8 Mar 2009 12:36:17 +0000 (UTC) (envelope-from ticso@cicely7.cicely.de) Received: from cicely5.cicely.de ([10.1.1.7]) by raven.bwct.de (8.13.4/8.13.4) with ESMTP id n28CaFqp015103 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Sun, 8 Mar 2009 13:36:16 +0100 (CET) (envelope-from ticso@cicely7.cicely.de) Received: from cicely7.cicely.de (cicely7.cicely.de [10.1.1.9]) by cicely5.cicely.de (8.14.2/8.14.2) with ESMTP id n28Ca9lS019398 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Sun, 8 Mar 2009 13:36:10 +0100 (CET) (envelope-from ticso@cicely7.cicely.de) Received: from cicely7.cicely.de (localhost [127.0.0.1]) by cicely7.cicely.de (8.14.2/8.14.2) with ESMTP id n28Ca9IG083909; Sun, 8 Mar 2009 13:36:09 +0100 (CET) (envelope-from ticso@cicely7.cicely.de) Received: (from ticso@localhost) by cicely7.cicely.de (8.14.2/8.14.2/Submit) id n28Ca9I9083908; Sun, 8 Mar 2009 13:36:09 +0100 (CET) (envelope-from ticso) Date: Sun, 8 Mar 2009 13:36:09 +0100 From: Bernd Walter To: "Rick C. Petty" Message-ID: <20090308123608.GC82478@cicely7.cicely.de> References: <200903041938.n24Jcqdr060153@lurza.secnetix.de> <20090304195614.GA179@britannica.bec.de> <20090306203057.GA49994@keira.kiwi-computer.com> <20090306214738.GA50654@keira.kiwi-computer.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090306214738.GA50654@keira.kiwi-computer.com> X-Operating-System: FreeBSD cicely7.cicely.de 7.0-STABLE i386 User-Agent: Mutt/1.5.11 X-Spam-Status: No, score=-4.4 required=5.0 tests=ALL_TRUSTED=-1.8, AWL=0.045, BAYES_00=-2.599 autolearn=ham version=3.2.5 X-Spam-Checker-Version: SpamAssassin 3.2.5 (2008-06-10) on spamd.cicely.de Cc: Octavian Covalschi , freebsd-hackers@freebsd.org Subject: Re: Spin down HDD after disk sync or before power off X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: ticso@cicely.de List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 08 Mar 2009 12:36:19 -0000 On Fri, Mar 06, 2009 at 03:47:38PM -0600, Rick C. Petty wrote: > On Fri, Mar 06, 2009 at 03:30:14PM -0600, Octavian Covalschi wrote: > > Why is spinning down is bad for HDD ? I believe it's better to spindown a > > drive, > > instead of cutting power too sudden. > > Comparing those two, I'd say it shouldn't matter (although probably a > forced spindown may be better). But pulling power from a drive does not > mean the drive immediately stops doing stuff. My understanding is that without power the heads just slamm into landing zone, while it can be done in a controlled smooth way with power. > I was just saying spindown on disks is bad in the first place. Sure, you > might save some wear and tear on the bearings, but you risk problems with > the heads on both spindown and spinup. In other words, if you can avoid > power-cycling your drives, they should last longer (in that you're less > likely to destroy the heads). This depends on the disks. Desktop and especially mobile drives are designed to sustain more spin downs, but are not designed for rotating a long time. But of course if you intend to spin up directly after spin down it might be bad for them as well, since it isn't really saving spinning time. This is nothing, which should be done on reboot, but for halts it might be reasonable to do. -- B.Walter http://www.bwct.de Modbus/TCP Ethernet I/O Baugruppen, ARM basierte FreeBSD Rechner uvm.