svn commit: r44663 - head/en_US.ISO8859-1/books/handbook/geom
Dru Lavigne
dru at FreeBSD.org
Fri Apr 25 15:26:07 UTC 2014
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>
More information about the svn-doc-head
mailing list