From owner-freebsd-stable@FreeBSD.ORG Sat Jun 11 19:50:48 2005 Return-Path: X-Original-To: stable@freebsd.org Delivered-To: freebsd-stable@FreeBSD.ORG Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id C823E16A41C for ; Sat, 11 Jun 2005 19:50:48 +0000 (GMT) (envelope-from paul@gromit.dlib.vt.edu) Received: from gromit.dlib.vt.edu (gromit.dlib.vt.edu [128.173.49.29]) by mx1.FreeBSD.org (Postfix) with ESMTP id 676B843D1D for ; Sat, 11 Jun 2005 19:50:48 +0000 (GMT) (envelope-from paul@gromit.dlib.vt.edu) Received: from zappa.Chelsea-Ct.Org (pool-151-199-7-31.ROA.east.verizon.net [151.199.7.31]) by gromit.dlib.vt.edu (8.13.3/8.13.3) with ESMTP id j5BJojp6088295 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Sat, 11 Jun 2005 15:50:47 -0400 (EDT) (envelope-from paul@gromit.dlib.vt.edu) Received: from zappa.Chelsea-Ct.Org (localhost.Chelsea-Ct.Org [127.0.0.1]) by zappa.Chelsea-Ct.Org (8.13.3/8.13.3) with ESMTP id j5BJodfT007315 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Sat, 11 Jun 2005 15:50:40 -0400 (EDT) (envelope-from paul@gromit.dlib.vt.edu) Received: (from paul@localhost) by zappa.Chelsea-Ct.Org (8.13.3/8.13.3/Submit) id j5BJocCL007314; Sat, 11 Jun 2005 15:50:38 -0400 (EDT) (envelope-from paul@gromit.dlib.vt.edu) X-Authentication-Warning: zappa.Chelsea-Ct.Org: paul set sender to paul@gromit.dlib.vt.edu using -f From: Paul Mather To: Mike Jakubik In-Reply-To: <1379.172.16.0.199.1118515349.squirrel@172.16.0.1> References: <1379.172.16.0.199.1118515349.squirrel@172.16.0.1> Content-Type: text/plain Content-Transfer-Encoding: 7bit Date: Sat, 11 Jun 2005 15:50:37 -0400 Message-Id: <1118519437.7105.16.camel@zappa.Chelsea-Ct.Org> Mime-Version: 1.0 X-Mailer: Evolution 2.2.3 FreeBSD GNOME Team Port Cc: stable@freebsd.org Subject: Re: atacontrol raid1 vs. gmirror X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 11 Jun 2005 19:50:48 -0000 On Sat, 2005-06-11 at 14:42 -0400, Mike Jakubik wrote: > Can someone explain tome the difference between a RAID1 setup done via > atacontrol and gmirror? I have a VIA 6420 SATA150 controller, which also > has raid, but is not supported by -stable. Here are the main differences, as I see them: atacontrol RAID: - Only for ATA; - Compatible with quite a few ATA RAID card BIOS metadata formats, hence you can create the RAID using the RAID controller's BIOS menu; - Supports only two-way mirroring (IIRC); - Supports spares. gmirror: - Works with any GEOM provider (ATA, SCSI, ggate, etc.); - Uses the last sector of each RAID component to store its own metadata; - Supports N-way mirroring; - Does not support spares (though gmirror activate/deactivate can be used to associate a component with a mirror somewhat akin to having a spare). I found array rebuilding to be troublesome on atacontrol RAID---so much so I abandoned it and used vinum and then gmirror instead for my RAID 1. (I have a bootable geom_mirror setup, now.) Mind you, that was in the pre-ATA mk.III days, and I hear the RAID support underwent a big revamp in the mk.III rewrite. Cheers, Paul. -- e-mail: paul@gromit.dlib.vt.edu "Without music to decorate it, time is just a bunch of boring production deadlines or dates by which bills must be paid." --- Frank Vincent Zappa