From owner-svn-doc-all@FreeBSD.ORG Fri Apr 25 16:10:59 2014 Return-Path: Delivered-To: svn-doc-all@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id E15CA164; Fri, 25 Apr 2014 16:10:58 +0000 (UTC) Received: from svn.freebsd.org (svn.freebsd.org [IPv6:2001:1900:2254:2068::e6a:0]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id CE4BF16C9; Fri, 25 Apr 2014 16:10:58 +0000 (UTC) Received: from svn.freebsd.org ([127.0.1.70]) by svn.freebsd.org (8.14.8/8.14.8) with ESMTP id s3PGAwx1012722; Fri, 25 Apr 2014 16:10:58 GMT (envelope-from dru@svn.freebsd.org) Received: (from dru@localhost) by svn.freebsd.org (8.14.8/8.14.8/Submit) id s3PGAwMV012721; Fri, 25 Apr 2014 16:10:58 GMT (envelope-from dru@svn.freebsd.org) Message-Id: <201404251610.s3PGAwMV012721@svn.freebsd.org> From: Dru Lavigne Date: Fri, 25 Apr 2014 16:10:58 +0000 (UTC) To: doc-committers@freebsd.org, svn-doc-all@freebsd.org, svn-doc-head@freebsd.org Subject: svn commit: r44664 - head/en_US.ISO8859-1/books/handbook/geom X-SVN-Group: doc-head MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: svn-doc-all@freebsd.org X-Mailman-Version: 2.1.17 Precedence: list List-Id: "SVN commit messages for the entire doc trees \(except for " user" , " projects" , and " translations" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 25 Apr 2014 16:10:59 -0000 Author: dru Date: Fri Apr 25 16:10:58 2014 New Revision: 44664 URL: http://svnweb.freebsd.org/changeset/doc/44664 Log: Editorial review of RAID3 chapter. Sponsored by: iXsystems Modified: head/en_US.ISO8859-1/books/handbook/geom/chapter.xml Modified: head/en_US.ISO8859-1/books/handbook/geom/chapter.xml ============================================================================== --- head/en_US.ISO8859-1/books/handbook/geom/chapter.xml Fri Apr 25 15:26:06 2014 (r44663) +++ head/en_US.ISO8859-1/books/handbook/geom/chapter.xml Fri Apr 25 16:10:58 2014 (r44664) @@ -895,8 +895,8 @@ mountroot> In a RAID3 system, data is split up into a number of bytes that are written across all the drives in the array except for one disk which acts as a dedicated parity disk. - This means that reading 1024KB from a - RAID3 implementation will access all disks in + This means that disk reads from a + RAID3 implementation access all disks in the array. Performance can be enhanced by using multiple disk controllers. The RAID3 array provides a fault tolerance of 1 drive, while providing a capacity of 1 - @@ -907,10 +907,19 @@ mountroot> At least 3 physical hard drives are required to build a RAID3 array. Each disk must be of the same - size, since I/O requests are interleaved to read or write to + size, since I/O requests are interleaved to read or write to multiple disks in parallel. Also, due to the nature of RAID3, the number of drives must be equal to 3, 5, 9, 17, and so on, or 2^n + 1. + + This section demonstrates how to create a software + RAID3 on a &os; system. + + + While it is theoretically possible to boot from a + RAID3 array on &os;, that configuration + is uncommon and is not advised. + Creating a Dedicated <acronym>RAID</acronym>3 @@ -922,30 +931,24 @@ mountroot></screen> <acronym>RAID</acronym>3 array on &os; requires the following steps.</para> - <note> - <para>While it is theoretically possible to boot from a - <acronym>RAID</acronym>3 array on &os;, that configuration - is uncommon and is not advised.</para> - </note> - <procedure> <step> <para>First, load the <filename>geom_raid3.ko</filename> - kernel module by issuing the following command:</para> + kernel module by issuing one of the following commands:</para> <screen>&prompt.root; <userinput>graid3 load</userinput></screen> - <para>Alternatively, it is possible to manually load the - <filename>geom_raid3.ko</filename> module:</para> + <para>or:</para> - <screen>&prompt.root; <userinput>kldload geom_raid3.ko</userinput></screen> + <screen>&prompt.root; <userinput>kldload geom_raid3</userinput></screen> </step> <step> - <para>Create or ensure that a suitable mount point - exists:</para> + <para>Ensure that a suitable mount point + exists. This command creates a new directory to use as + the mount point:</para> - <screen>&prompt.root; <userinput>mkdir <replaceable>/multimedia/</replaceable></userinput></screen> + <screen>&prompt.root; <userinput>mkdir <replaceable>/multimedia</replaceable></userinput></screen> </step> <step> @@ -971,7 +974,7 @@ Done.</screen> <step> <para>Partition the newly created - <filename>gr0</filename> device and put a UFS file + <filename>gr0</filename> device and put a <acronym>UFS</acronym> file system on it:</para> <screen>&prompt.root; <userinput>gpart create -s GPT /dev/raid3/gr0</userinput> @@ -989,7 +992,7 @@ Done.</screen> </step> </procedure> - <para>Additional configuration is needed to retain the above + <para>Additional configuration is needed to retain this setup across system reboots.</para> <procedure>