From owner-freebsd-questions@FreeBSD.ORG Tue Jun 10 15:05:40 2008 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 1A1C11065679 for ; Tue, 10 Jun 2008 15:05:40 +0000 (UTC) (envelope-from erikt@midgard.homeip.net) Received: from ch-smtp02.sth.basefarm.net (ch-smtp02.sth.basefarm.net [80.76.149.213]) by mx1.freebsd.org (Postfix) with ESMTP id CE9D28FC19 for ; Tue, 10 Jun 2008 15:05:39 +0000 (UTC) (envelope-from erikt@midgard.homeip.net) Received: from c83-253-25-183.bredband.comhem.se ([83.253.25.183]:62448 helo=falcon.midgard.homeip.net) by ch-smtp02.sth.basefarm.net with esmtp (Exim 4.68) (envelope-from ) id 1K65Pm-0007LO-8n for freebsd-questions@freebsd.org; Tue, 10 Jun 2008 17:05:39 +0200 Received: (qmail 76398 invoked from network); 10 Jun 2008 17:05:36 +0200 Received: from owl.midgard.homeip.net (10.1.5.7) by falcon.midgard.homeip.net with ESMTP; 10 Jun 2008 17:05:36 +0200 Received: (qmail 67100 invoked by uid 1001); 10 Jun 2008 17:05:36 +0200 Date: Tue, 10 Jun 2008 17:05:36 +0200 From: Erik Trulsson To: Wojciech Puchar Message-ID: <20080610150536.GA67056@owl.midgard.homeip.net> References: <484EACEB.7169.43FE1258@iwrtech.iwr.ru.ac.za> <20080610165435.M68290@wojtek.tensor.gdynia.pl> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20080610165435.M68290@wojtek.tensor.gdynia.pl> User-Agent: Mutt/1.5.18 (2008-05-17) X-Originating-IP: 83.253.25.183 X-Scan-Result: No virus found in message 1K65Pm-0007LO-8n. X-Scan-Signature: ch-smtp02.sth.basefarm.net 1K65Pm-0007LO-8n c749beae0d56439fc788e229534e164d Cc: freebsd-questions@freebsd.org, DA Forsyth Subject: Re: xRAID disks.... X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 10 Jun 2008 15:05:40 -0000 On Tue, Jun 10, 2008 at 04:56:07PM +0200, Wojciech Puchar wrote: > > > > The pair of ex-RAID disks are ad1 and ad2 and obviously are no longer > > a raid pair, yet 'something' is telling the ar() driver to try and > > pair them and failing because there is no raid hardware in that box. > > there are no "raid hardware" on most devices. it's just marketing hype. Most (cheap) RAID controllers do almost everything in software. Some do have hardware support. > actually there is not much need to have it for RAID-0/1/10 where there is > almostnothing to process. For mirrors it can actually be a big win with hardware support. If you use software RAID then you will have to perform each write twice (once to each disk), while with hardware support for RAID you only need to transfer the data once. If the controller resides on a PCI-bus together with several other devices (which is not uncommon) then the reduced bandwidth usage can be very useful. (And for RAID you will need at least some support on the controller if you want to be able to boot from a striped volume.) > > > purposes and has not shown any signs of knowing it was in a raid > > pair) > > > > I suspect the raidinfo is stored on the disk somewhere and a suitable > > 'dd' command can erase it. but where and how? > erase the whole drive. > > and next time don't use "hardware" RAID anymore. use gmirror and gstripe > to have PORTABLE RAID. -- Erik Trulsson ertr1013@student.uu.se