From owner-freebsd-hardware@FreeBSD.ORG Tue Oct 12 22:13:55 2004 Return-Path: Delivered-To: freebsd-hardware@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id CE66D16A4CE for ; Tue, 12 Oct 2004 22:13:55 +0000 (GMT) Received: from nargothrond.kdm.org (nargothrond.kdm.org [70.56.43.81]) by mx1.FreeBSD.org (Postfix) with ESMTP id 6EA3D43D2F for ; Tue, 12 Oct 2004 22:13:55 +0000 (GMT) (envelope-from ken@nargothrond.kdm.org) Received: from nargothrond.kdm.org (localhost [127.0.0.1]) by nargothrond.kdm.org (8.12.11/8.12.11) with ESMTP id i9CMDo7e089611; Tue, 12 Oct 2004 16:13:50 -0600 (MDT) (envelope-from ken@nargothrond.kdm.org) Received: (from ken@localhost) by nargothrond.kdm.org (8.12.11/8.12.5/Submit) id i9CMDktg089610; Tue, 12 Oct 2004 16:13:46 -0600 (MDT) (envelope-from ken) Date: Tue, 12 Oct 2004 16:13:46 -0600 From: "Kenneth D. Merry" To: Roisin Murphy Message-ID: <20041012221346.GA89589@nargothrond.kdm.org> References: <20041011043508.GA72113@nargothrond.kdm.org> <20041011210303.GA78436@nargothrond.kdm.org> <20041012171106.GB86646@nargothrond.kdm.org> <20041012215951.GA89335@nargothrond.kdm.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.2i X-Virus-Scanned: clamd / ClamAV version 0.75.1, clamav-milter version 0.75c on nargothrond.kdm.org X-Virus-Status: Clean cc: freebsd-hardware@freebsd.org Subject: Re: sata raid & write cache state X-BeenThere: freebsd-hardware@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: General discussion of FreeBSD hardware List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 12 Oct 2004 22:13:55 -0000 On Tue, Oct 12, 2004 at 15:10:38 -0700, Roisin Murphy wrote: > > Head to www.apc.com and look at the UPSes they have there. They're > > basically lead acid batteries with inverters to put out A/C power when your > > main power feed goes out. > > i meant the battery option they sell with some raid controllers, is > this and extra little PSU, that also powers the disks for a while, or > is this just meant to keep the raid controller's cache powered till > the machine boots up again, so it can finish its cache flush? It just powers the cache until the machine boots again and the controller can flush the cache out. Ken -- Kenneth Merry ken@FreeBSD.ORG