From owner-freebsd-multimedia@FreeBSD.ORG Sat Jan 31 08:47:47 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 0E53616A4CE for ; Sat, 31 Jan 2004 08:47:47 -0800 (PST) Received: from rwcrmhc13.comcast.net (rwcrmhc13.comcast.net [204.127.198.39]) by mx1.FreeBSD.org (Postfix) with ESMTP id 7F42543D41 for ; Sat, 31 Jan 2004 08:47:43 -0800 (PST) (envelope-from julian@elischer.org) Received: from interjet.elischer.org ([24.7.73.28]) by comcast.net (rwcrmhc13) with ESMTP id <2004013116474201500ovkr2e>; Sat, 31 Jan 2004 16:47:43 +0000 Received: from localhost (localhost.elischer.org [127.0.0.1]) by InterJet.elischer.org (8.9.1a/8.9.1) with ESMTP id IAA43727; Sat, 31 Jan 2004 08:47:40 -0800 (PST) Date: Sat, 31 Jan 2004 08:47:38 -0800 (PST) From: Julian Elischer To: Bjorn Eikeland In-Reply-To: Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII cc: "freebsd-multimedia@freebsd.org" cc: cpghost@cordula.ws 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 16:47:47 -0000 On Sat, 31 Jan 2004, Bjorn Eikeland wrote: > 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 there is a port "ataidle" that sets teh IDE drive's internal idle timeout timer so it will spin down if you dont use it.. as for scsi, you can sent it a spin-down command with camcontrol but I forget the actual command.. (it should be in the scsi .h files) julian > > 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. > > > > > _______________________________________________ > freebsd-multimedia@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-multimedia > To unsubscribe, send any mail to "freebsd-multimedia-unsubscribe@freebsd.org" >