Date: Fri, 25 Apr 2014 15:26:06 +0000 (UTC) From: Dru Lavigne <dru@FreeBSD.org> To: doc-committers@freebsd.org, svn-doc-all@freebsd.org, svn-doc-head@freebsd.org Subject: svn commit: r44663 - head/en_US.ISO8859-1/books/handbook/geom Message-ID: <201404251526.s3PFQ6pX094867@svn.freebsd.org>
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Author: dru Date: Fri Apr 25 15:26:06 2014 New Revision: 44663 URL: http://svnweb.freebsd.org/changeset/doc/44663 Log: Put RAID3 chapter before Software RAID Devices 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 14:48:46 2014 (r44662) +++ head/en_US.ISO8859-1/books/handbook/geom/chapter.xml Fri Apr 25 15:26:06 2014 (r44663) @@ -842,6 +842,179 @@ mountroot></screen> </sect2> </sect1> + <sect1 xml:id="geom-raid3"> + <info> + + <title><acronym>RAID</acronym>3 - Byte-level Striping with + Dedicated Parity</title> + + <authorgroup> + <author> + <personname> + <firstname>Mark</firstname> + <surname>Gladman</surname> + </personname> + <contrib>Written by </contrib> + </author> + + <author> + <personname> + <firstname>Daniel</firstname> + <surname>Gerzo</surname> + </personname> + </author> + </authorgroup> + + <authorgroup> + <author> + <personname> + <firstname>Tom</firstname> + <surname>Rhodes</surname> + </personname> + <contrib>Based on documentation by </contrib> + </author> + + <author> + <personname> + <firstname>Murray</firstname> + <surname>Stokely</surname> + </personname> + </author> + </authorgroup> + </info> + + <indexterm> + <primary><acronym>GEOM</acronym></primary> + </indexterm> + <indexterm> + <primary>RAID3</primary> + </indexterm> + + <para><acronym>RAID</acronym>3 is a method used to combine several + disk drives into a single volume with a dedicated parity disk. + In a <acronym>RAID</acronym>3 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 + <acronym>RAID</acronym>3 implementation will access all disks in + the array. Performance can be enhanced by using multiple disk + controllers. The <acronym>RAID</acronym>3 array provides a + fault tolerance of 1 drive, while providing a capacity of 1 - + 1/n times the total capacity of all drives in the array, where n + is the number of hard drives in the array. Such a configuration + is mostly suitable for storing data of larger sizes such as + multimedia files.</para> + + <para>At least 3 physical hard drives are required to build a + <acronym>RAID</acronym>3 array. Each disk must be of the same + size, since I/O requests are interleaved to read or write to + multiple disks in parallel. Also, due to the nature of + <acronym>RAID</acronym>3, the number of drives must be + equal to 3, 5, 9, 17, and so on, or 2^n + 1.</para> + + <sect2> + <title>Creating a Dedicated <acronym>RAID</acronym>3 + Array</title> + + <para>In &os;, support for <acronym>RAID</acronym>3 is + implemented by the &man.graid3.8; <acronym>GEOM</acronym> + class. Creating a dedicated + <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> + + <screen>&prompt.root; <userinput>graid3 load</userinput></screen> + + <para>Alternatively, it is possible to manually load the + <filename>geom_raid3.ko</filename> module:</para> + + <screen>&prompt.root; <userinput>kldload geom_raid3.ko</userinput></screen> + </step> + + <step> + <para>Create or ensure that a suitable mount point + exists:</para> + + <screen>&prompt.root; <userinput>mkdir <replaceable>/multimedia/</replaceable></userinput></screen> + </step> + + <step> + <para>Determine the device names for the disks which will be + added to the array, and create the new + <acronym>RAID</acronym>3 device. The final device listed + will act as the dedicated parity disk. This + example uses three unpartitioned + <acronym>ATA</acronym> drives: + <filename><replaceable>ada1</replaceable></filename> + and + <filename><replaceable>ada2</replaceable></filename> + for data, and + <filename><replaceable>ada3</replaceable></filename> + for parity.</para> + + <screen>&prompt.root; <userinput>graid3 label -v gr0 /dev/ada1 /dev/ada2 /dev/ada3</userinput> +Metadata value stored on /dev/ada1. +Metadata value stored on /dev/ada2. +Metadata value stored on /dev/ada3. +Done.</screen> + </step> + + <step> + <para>Partition the newly created + <filename>gr0</filename> device and put a UFS file + system on it:</para> + + <screen>&prompt.root; <userinput>gpart create -s GPT /dev/raid3/gr0</userinput> +&prompt.root; <userinput>gpart add -t freebsd-ufs /dev/raid3/gr0</userinput> +&prompt.root; <userinput>newfs -j /dev/raid3/gr0p1</userinput></screen> + + <para>Many numbers will glide across the screen, and after a + bit of time, the process will be complete. The volume has + been created and is ready to be mounted:</para> + + <screen>&prompt.root; <userinput>mount /dev/raid3/gr0p1 /multimedia/</userinput></screen> + + <para>The <acronym>RAID</acronym>3 array is now ready to + use.</para> + </step> + </procedure> + + <para>Additional configuration is needed to retain the above + setup across system reboots.</para> + + <procedure> + <step> + <para>The <filename>geom_raid3.ko</filename> module must be + loaded before the array can be mounted. To automatically + load the kernel module during system initialization, add + the following line to + <filename>/boot/loader.conf</filename>:</para> + + <programlisting>geom_raid3_load="YES"</programlisting> + </step> + + <step> + <para>The following volume information must be added to + <filename>/etc/fstab</filename> in order to + automatically mount the array's file system during + the system boot process:</para> + + <programlisting>/dev/raid3/gr0p1 /multimedia ufs rw 2 2</programlisting> + </step> + </procedure> + </sect2> + </sect1> + <sect1 xml:id="geom-graid"> <info> <title>Software <acronym>RAID</acronym> Devices</title> @@ -1153,179 +1326,6 @@ raid/r0 OPTIMAL ada0 (ACTIVE (ACTIVE)) </sect2> </sect1> - <sect1 xml:id="geom-raid3"> - <info> - - <title><acronym>RAID</acronym>3 - Byte-level Striping with - Dedicated Parity</title> - - <authorgroup> - <author> - <personname> - <firstname>Mark</firstname> - <surname>Gladman</surname> - </personname> - <contrib>Written by </contrib> - </author> - - <author> - <personname> - <firstname>Daniel</firstname> - <surname>Gerzo</surname> - </personname> - </author> - </authorgroup> - - <authorgroup> - <author> - <personname> - <firstname>Tom</firstname> - <surname>Rhodes</surname> - </personname> - <contrib>Based on documentation by </contrib> - </author> - - <author> - <personname> - <firstname>Murray</firstname> - <surname>Stokely</surname> - </personname> - </author> - </authorgroup> - </info> - - <indexterm> - <primary><acronym>GEOM</acronym></primary> - </indexterm> - <indexterm> - <primary>RAID3</primary> - </indexterm> - - <para><acronym>RAID</acronym>3 is a method used to combine several - disk drives into a single volume with a dedicated parity disk. - In a <acronym>RAID</acronym>3 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 - <acronym>RAID</acronym>3 implementation will access all disks in - the array. Performance can be enhanced by using multiple disk - controllers. The <acronym>RAID</acronym>3 array provides a - fault tolerance of 1 drive, while providing a capacity of 1 - - 1/n times the total capacity of all drives in the array, where n - is the number of hard drives in the array. Such a configuration - is mostly suitable for storing data of larger sizes such as - multimedia files.</para> - - <para>At least 3 physical hard drives are required to build a - <acronym>RAID</acronym>3 array. Each disk must be of the same - size, since I/O requests are interleaved to read or write to - multiple disks in parallel. Also, due to the nature of - <acronym>RAID</acronym>3, the number of drives must be - equal to 3, 5, 9, 17, and so on, or 2^n + 1.</para> - - <sect2> - <title>Creating a Dedicated <acronym>RAID</acronym>3 - Array</title> - - <para>In &os;, support for <acronym>RAID</acronym>3 is - implemented by the &man.graid3.8; <acronym>GEOM</acronym> - class. Creating a dedicated - <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> - - <screen>&prompt.root; <userinput>graid3 load</userinput></screen> - - <para>Alternatively, it is possible to manually load the - <filename>geom_raid3.ko</filename> module:</para> - - <screen>&prompt.root; <userinput>kldload geom_raid3.ko</userinput></screen> - </step> - - <step> - <para>Create or ensure that a suitable mount point - exists:</para> - - <screen>&prompt.root; <userinput>mkdir <replaceable>/multimedia/</replaceable></userinput></screen> - </step> - - <step> - <para>Determine the device names for the disks which will be - added to the array, and create the new - <acronym>RAID</acronym>3 device. The final device listed - will act as the dedicated parity disk. This - example uses three unpartitioned - <acronym>ATA</acronym> drives: - <filename><replaceable>ada1</replaceable></filename> - and - <filename><replaceable>ada2</replaceable></filename> - for data, and - <filename><replaceable>ada3</replaceable></filename> - for parity.</para> - - <screen>&prompt.root; <userinput>graid3 label -v gr0 /dev/ada1 /dev/ada2 /dev/ada3</userinput> -Metadata value stored on /dev/ada1. -Metadata value stored on /dev/ada2. -Metadata value stored on /dev/ada3. -Done.</screen> - </step> - - <step> - <para>Partition the newly created - <filename>gr0</filename> device and put a UFS file - system on it:</para> - - <screen>&prompt.root; <userinput>gpart create -s GPT /dev/raid3/gr0</userinput> -&prompt.root; <userinput>gpart add -t freebsd-ufs /dev/raid3/gr0</userinput> -&prompt.root; <userinput>newfs -j /dev/raid3/gr0p1</userinput></screen> - - <para>Many numbers will glide across the screen, and after a - bit of time, the process will be complete. The volume has - been created and is ready to be mounted:</para> - - <screen>&prompt.root; <userinput>mount /dev/raid3/gr0p1 /multimedia/</userinput></screen> - - <para>The <acronym>RAID</acronym>3 array is now ready to - use.</para> - </step> - </procedure> - - <para>Additional configuration is needed to retain the above - setup across system reboots.</para> - - <procedure> - <step> - <para>The <filename>geom_raid3.ko</filename> module must be - loaded before the array can be mounted. To automatically - load the kernel module during system initialization, add - the following line to - <filename>/boot/loader.conf</filename>:</para> - - <programlisting>geom_raid3_load="YES"</programlisting> - </step> - - <step> - <para>The following volume information must be added to - <filename>/etc/fstab</filename> in order to - automatically mount the array's file system during - the system boot process:</para> - - <programlisting>/dev/raid3/gr0p1 /multimedia ufs rw 2 2</programlisting> - </step> - </procedure> - </sect2> - </sect1> - <sect1 xml:id="geom-ggate"> <title><acronym>GEOM</acronym> Gate Network Devices</title>
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