From owner-freebsd-hackers@FreeBSD.ORG Thu Feb 4 03:43:23 2010 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 B4FFD106566C for ; Thu, 4 Feb 2010 03:43:23 +0000 (UTC) (envelope-from wblock@wonkity.com) Received: from wonkity.com (wonkity.com [67.158.26.137]) by mx1.freebsd.org (Postfix) with ESMTP id 6C0408FC1C for ; Thu, 4 Feb 2010 03:43:23 +0000 (UTC) Received: from wonkity.com (localhost [127.0.0.1]) by wonkity.com (8.14.3/8.14.3) with ESMTP id o143hLVn011304; Wed, 3 Feb 2010 20:43:21 -0700 (MST) (envelope-from wblock@wonkity.com) Received: from localhost (wblock@localhost) by wonkity.com (8.14.3/8.14.3/Submit) with ESMTP id o143hLxh011301; Wed, 3 Feb 2010 20:43:21 -0700 (MST) (envelope-from wblock@wonkity.com) Date: Wed, 3 Feb 2010 20:43:21 -0700 (MST) From: Warren Block To: Erich Dollansky In-Reply-To: <201002041009.05222.erich@alogreentechnologies.com> Message-ID: References: <201002031343.o13Dhj7i052507@lurza.secnetix.de> <201002041009.05222.erich@alogreentechnologies.com> User-Agent: Alpine 2.00 (BSF 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; format=flowed; charset=US-ASCII X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.2.3 (wonkity.com [127.0.0.1]); Wed, 03 Feb 2010 20:43:21 -0700 (MST) Cc: 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 List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 04 Feb 2010 03:43:23 -0000 On Thu, 4 Feb 2010, Erich Dollansky wrote: > let me do. > > On 04 February 2010 am 04:44:04 Warren Block wrote: >> On Wed, 3 Feb 2010, Oliver Fromme wrote: >> >>> Alexander Best wrote: >>> No -- *Please* make sure that the disks are only spun down >>> upon an actual power-off command (i.e. when reboot() is >> >> Could you elaborate a little on why that's bad? It seems like it would >> be similar to a standby/resume action. >> > every disk has a limited number of restarts before it dies. Okay. For future reference, here are the numbers I've seen: power cycles (Seagate): 50,000 lifetime normal head load/unload (Hitachi): 600,000 lifetime emergency head load/unload (Hitachi): 20,000 lifetime > In case of a reboot, it is already known when the command is given that the machine will restart without being powered of. > > If you spin-down the disk, you lose one start cycle. > > It is not that important but if it can be done with just one if, please, just do it. AFAICT ad_shutdown can't tell whether it's called for a reboot or a poweroff, it's just told to "shut down". So maybe it's one if, but it's somewhere above ata-disk.c but below reboot(RB_POWEROFF). -Warren Block * Rapid City, South Dakota USA