From owner-freebsd-geom@FreeBSD.ORG Sat Jan 13 04:25:42 2007 Return-Path: X-Original-To: freebsd-geom@freebsd.org Delivered-To: freebsd-geom@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id 9451E16A40F for ; Sat, 13 Jan 2007 04:25:42 +0000 (UTC) (envelope-from anderson@centtech.com) Received: from mh1.centtech.com (moat3.centtech.com [64.129.166.50]) by mx1.freebsd.org (Postfix) with ESMTP id 6900813C442 for ; Sat, 13 Jan 2007 04:25:42 +0000 (UTC) (envelope-from anderson@centtech.com) Received: from [192.168.42.21] (andersonbox1.centtech.com [192.168.42.21]) by mh1.centtech.com (8.13.8/8.13.8) with ESMTP id l0D4PYAt049234; Fri, 12 Jan 2007 22:25:39 -0600 (CST) (envelope-from anderson@centtech.com) Message-ID: <45A85F40.7050703@centtech.com> Date: Fri, 12 Jan 2007 22:25:36 -0600 From: Eric Anderson User-Agent: Thunderbird 1.5.0.9 (X11/20061223) MIME-Version: 1.0 To: Jeremie Le Hen References: <20070113004728.GQ2616@obiwan.tataz.chchile.org> In-Reply-To: <20070113004728.GQ2616@obiwan.tataz.chchile.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Virus-Scanned: ClamAV 0.88.4/2437/Thu Jan 11 17:59:09 2007 on mh1.centtech.com X-Virus-Status: Clean X-Spam-Status: No, score=-2.5 required=8.0 tests=AWL,BAYES_00 autolearn=ham version=3.1.6 X-Spam-Checker-Version: SpamAssassin 3.1.6 (2006-10-03) on mh1.centtech.com Cc: freebsd-geom@freebsd.org Subject: Re: What is gstripe ? 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: Sat, 13 Jan 2007 04:25:42 -0000 On 01/12/07 18:47, Jeremie Le Hen wrote: > Hi list, > > Please forgive me, I know this is a dumb question. I've checked the > manpage, Wikipedia [1], Webopedia [2] and a few other documents, > but I'm still not sure to fully understand the striping concept. > > gmirror(8) provides RAID-1 and is very easy to understand. > gconcat(8) is easy to grasp as well. > > However, I'm experiencing some difficulties to understand gstripe(8). > I would say it's a kind of smart disk concatenation which stores > block X on disk (X % N), where N is the number of disk in the RAID-0. > This permits faster read/write. > > Am I right ? > > [1] http://en.wikipedia.org/wiki/Data_striping > [2] http://www.webopedia.com/TERM/R/RAID.html > > Thank you. > Best regards, Yea, that's pretty close! A stripe (RAID 0 - called that because it really isn't redundant in any way) is just like you described. Write one block to the first disk, then the next block to the next disk, etc. It distributes your read/write activity to increase performance. Sequential read/write performance may not be affected, but random IO should get a nice boost. See this site for some pretty graphics: http://www.raid.com/04_00.html or more specifically: http://www.raid.com/04_01_00.html Eric -- ------------------------------------------------------------------------ Eric Anderson Sr. Systems Administrator Centaur Technology An undefined problem has an infinite number of solutions. ------------------------------------------------------------------------