From owner-freebsd-hackers@FreeBSD.ORG Mon Apr 9 20:25:32 2007 Return-Path: X-Original-To: freebsd-hackers@freebsd.org Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id 45A4F16A401 for ; Mon, 9 Apr 2007 20:25:32 +0000 (UTC) (envelope-from youshi10@u.washington.edu) Received: from mxout7.cac.washington.edu (mxout7.cac.washington.edu [140.142.32.178]) by mx1.freebsd.org (Postfix) with ESMTP id DDCF413C487 for ; Mon, 9 Apr 2007 20:25:31 +0000 (UTC) (envelope-from youshi10@u.washington.edu) Received: from hymn09.u.washington.edu (hymn09.u.washington.edu [140.142.12.183]) by mxout7.cac.washington.edu (8.13.7+UW06.06/8.13.7+UW07.03) with ESMTP id l39KPSdR008345 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Mon, 9 Apr 2007 13:25:28 -0700 Received: from localhost (localhost [127.0.0.1]) by hymn09.u.washington.edu (8.13.7+UW06.06/8.13.7+UW07.03) with ESMTP id l39KPSNY014227 for ; Mon, 9 Apr 2007 13:25:28 -0700 X-Auth-Received: from [134.134.136.2] by hymn09.u.washington.edu via HTTP; Mon, 09 Apr 2007 13:25:28 PDT Date: Mon, 9 Apr 2007 13:25:28 -0700 (PDT) From: youshi10@u.washington.edu To: freebsd-hackers@freebsd.org In-Reply-To: <20070409195624.GA87746@keira.kiwi-computer.com> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed X-PMX-Version: 5.3.0.289146, Antispam-Engine: 2.5.0.283055, Antispam-Data: 2007.4.9.131233 X-Uwash-Spam: Gauge=IIIIIII, Probability=7%, Report='NO_REAL_NAME 0, __CT 0, __CT_TEXT_PLAIN 0, __HAS_MSGID 0, __MIME_TEXT_ONLY 0, __MIME_VERSION 0, __SANE_MSGID 0' Subject: Re: Discovering list of open files from "kernel level" without using utils like lsof 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: Mon, 09 Apr 2007 20:25:32 -0000 On Mon, 9 Apr 2007, Rick C. Petty wrote: > On Sun, Apr 08, 2007 at 11:05:48AM -0700, Garrett Cooper wrote: >> I'm trying to see if there's a simple tool that I could code in C/C++ >> if necessary to spin down disks automatically to save power and disk >> life. Plus, I think that lsof actually would probe the devices and 'wake >> them up' instead of keeping them as-is. However, I could be wrong so if >> I am please let me know. > > I read somewhere once that keeping disks spinning makes them last 10x > longer. > > Personally, I've seen more disk failures on workstations which are > power-cycled regularly than on systems which are always running. > > I've also seen disks work just fine while powered that just plain quit > immediately after a power cycle. > > So you may save power by spinning the disks down, but I doubt you're > saving disk life (unless they're powered down for weeks at a time). > > -- Rick C. Petty Hence the followup post. -Garrett