From owner-freebsd-geom@FreeBSD.ORG Tue Oct 30 04:34:49 2007 Return-Path: Delivered-To: freebsd-geom@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id C235F16A419 for ; Tue, 30 Oct 2007 04:34:49 +0000 (UTC) (envelope-from tom.hurst@clara.net) Received: from spork.qfe3.net (spork.qfe3.net [212.13.207.101]) by mx1.freebsd.org (Postfix) with ESMTP id 84D7313C4AA for ; Tue, 30 Oct 2007 04:34:49 +0000 (UTC) (envelope-from tom.hurst@clara.net) Received: from [81.104.144.87] (helo=voi.aagh.net) by spork.qfe3.net with esmtp (Exim 4.66 (FreeBSD)) (envelope-from ) id 1ImiQJ-000OUJ-31; Tue, 30 Oct 2007 04:09:51 +0000 Received: from freaky by voi.aagh.net with local (Exim 4.68 (FreeBSD)) (envelope-from ) id 1ImiQI-000KCr-W2; Tue, 30 Oct 2007 04:09:51 +0000 Date: Tue, 30 Oct 2007 04:09:50 +0000 From: Thomas Hurst To: Kevin Thompson Message-ID: <20071030040950.GA76585@voi.aagh.net> Mail-Followup-To: Kevin Thompson , Felipe Neuwald , freebsd-geom@freebsd.org References: <4414.147.177.192.113.1193678595.squirrel@angst.csh.rit.edu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4414.147.177.192.113.1193678595.squirrel@angst.csh.rit.edu> Organization: Not much. User-Agent: Mutt/1.5.16 (2007-06-09) Sender: Thomas Hurst Cc: Felipe Neuwald , freebsd-geom@freebsd.org Subject: Re: Raid 0 + 1 X-BeenThere: freebsd-geom@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: GEOM-specific discussions and implementations List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 30 Oct 2007 04:34:49 -0000 * Kevin Thompson (antiduh@csh.rit.edu) wrote: > Now we're going to pull together the d partion on each drive, create > pairwise stripes, then mirror the new stripes together. > gstripe label -vh -s 131072 st0 /dev/label/geom0s1d /dev/geom1s1d > gstripe label -vh -s 131072 st1 /dev/label/geom2s1d /dev/geom3s1d > > We should now have two new devices '''/dev/stripe/st0''' and > '''/dev/stripe/st1'''. Now mirror those two devices to create our final > device that will next be used for the rest of our filesystems: > gmirror label -vh gm0 /dev/stripe/st0 /dev/stripe/st1 Er, shouldn't you be doing this the other way around? Make two mirrors, then stripe across them. IO performance should be identical in the normal case, degrade less with a single disk failure (since only one disk drops out of the array instead of an entire pair), and it'll be more likely to survive a two disk failure. -- Thomas 'Freaky' Hurst http://hur.st/