From owner-freebsd-multimedia@FreeBSD.ORG Sat Jan 31 06:29:20 2004 Return-Path: Delivered-To: freebsd-multimedia@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 33F5F16A4CE for ; Sat, 31 Jan 2004 06:29:20 -0800 (PST) Received: from mail.valuehost.co.uk (mail.valuehost.co.uk [62.25.99.6]) by mx1.FreeBSD.org (Postfix) with SMTP id 1036243D1F for ; Sat, 31 Jan 2004 06:29:18 -0800 (PST) (envelope-from bjorn@eikeland.info) Received: (qmail 85723 invoked by uid 89); 31 Jan 2004 14:29:08 +0000 Received: from unknown (HELO beer.eikeland.info) (bjorn@eikeland.info@80.202.106.8) by mail.valuehost.co.uk with SMTP; 31 Jan 2004 14:29:08 +0000 To: cpghost@cordula.ws, "freebsd-multimedia@freebsd.org" References: <20040131140833.69B9540823@fw.farid-hajji.net> Message-ID: From: Bjorn Eikeland Content-Type: text/plain; format=flowed; charset=iso-8859-15 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Date: Sat, 31 Jan 2004 15:29:22 +0100 In-Reply-To: <20040131140833.69B9540823@fw.farid-hajji.net> User-Agent: Opera7.23/FreeBSD M2 build 518 Subject: Re: Transferring the root filesystem to a ramdisk? X-BeenThere: freebsd-multimedia@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Multimedia discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 31 Jan 2004 14:29:20 -0000 I'm probably in over my head here, but; chroot should change the root filesystem for you. (look in the manpages for more details) As for powering down the hdd I did find a page for this, but havent had time to play with it yet: http://www.cran.org.uk/bruce/software.php best of luck! > Hello, > > in an attempt to save power on FreeBSD servers, I'm > trying to replace the hdd with a ramdisk. The idea is to: > > 1. boot from the hdd (or netboot from an NFS server) > 2. configure a ram disk (md(4)) > 3. copy everything that's needed to ram disk > 4. transfer kernel root to ramdisk (*) > 5. turn off the hdd (**) > > (*) is the hairy question. > (**) How can that be done? > > I won't need paging, because there'll be enough ram for > everything (ramdisk, kernel and userland). > > Now the questions are: > > * How to "attach" the root filesystem to the ram disk? > > Can this be done only through pxe/netboot before the > kernel starts, or is there some kind of system call > that can transfer root on a running system? > > * How to power off (and on) the hdd (both for ATA and SCSI)? > > * Will the power consumption decrease (no hdd) or will > it increase (more ram)? Anybody measured this before > with regular diskless machines? > > Thanks, > -cpghost. >