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Tidy up the ZFS section a bit, adjust the RAID-Z example from two to three

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drives and add a warning that the suggested configuration is between three
to nine disks.

PR:		135983
This commit is contained in:
Remko Lodder 2009-08-11 07:10:14 +00:00
parent 0852103709
commit 027dad28c0
Notes: svn2git 2020-12-08 03:00:23 +00:00 
svn path=/head/; revision=34603
1 changed files with 27 additions and 14 deletions
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41
en_US.ISO8859-1/books/handbook/filesystems/chapter.sgml
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@ -108,7 +108,7 @@
</sect1>
<sect1 id="filesystems-zfs">
<title>The Z File System</title>
<title>The Z File System (ZFS)</title>
<para>The Z&nbsp;file system, developed by &sun;, is a new
technology designed to use a pooled storage method. This means
@ -198,19 +198,20 @@ vfs.zfs.vdev.cache.size="5M"</programlisting>
<screen>&prompt.root; <userinput>echo 'zfs_enable="YES"' &gt;&gt; /etc/rc.conf</userinput>
&prompt.root; <userinput>/etc/rc.d/zfs start</userinput></screen>
<para>The remainder of this document assumes two
<para>The remainder of this document assumes three
<acronym>SCSI</acronym> disks are available, and their device names
are <devicename><replaceable>da0</replaceable></devicename>
and <devicename><replaceable>da1</replaceable></devicename>
respectively. Users of <acronym>IDE</acronym> hardware may
use the <devicename><replaceable>ad</replaceable></devicename>
are <devicename><replaceable>da0</replaceable></devicename>,
<devicename><replaceable>da1</replaceable></devicename>
and <devicename><replaceable>da2</replaceable></devicename>.
Users of <acronym>IDE</acronym> hardware may use the
<devicename><replaceable>ad</replaceable></devicename>
devices in place of <acronym>SCSI</acronym> hardware.</para>
<sect3>
<title>Single Disk Pool</title>
<para>To create a <acronym>ZFS</acronym> over a single disk
device, use the <command>zpool</command> command:</para>
<para>To create a simple, non-redundant <acronym>ZFS</acronym> pool using a
single disk device, use the <command>zpool</command> command:</para>
<screen>&prompt.root; <userinput>zpool create example /dev/da0</userinput></screen>
@ -340,13 +341,22 @@ example/data 17547008 0 17547008 0% /example/data</screen>
<title><acronym>ZFS</acronym> RAID-Z</title>
<para>As previously noted, this section will assume that
two <acronym>SCSI</acronym> exists as devices
<devicename>da0</devicename> and
<devicename>da1</devicename>. To create a
three <acronym>SCSI</acronym> disks exist as devices
<devicename>da0</devicename>, <devicename>da1</devicename>
and <devicename>da2</devicename> (or <devicename>ad0</devicename>
and beyond in case IDE disks are being used). To create a
<acronym>RAID</acronym>-Z pool, issue the following
command:</para>
<screen>&prompt.root; <userinput>zpool create storage raidz da0 da1</userinput></screen>
<screen>&prompt.root; <userinput>zpool create storage raidz da0 da1 da2</userinput></screen>
<warning><para>&sun; recommends that the amount of devices used in a
<acronym>RAID</acronym>-Z configuration is 3-9. If your needs
call for a single pool to consist of 10 disks or more, consider
breaking it up into smaller <acronym>RAID</acronym>-z groups. If
you only have 2 disks, and still require redundancy, consider using
the <acronym>ZFS</acronym> mirror feature. See the &man.zpool.8;
manual page for more details.</para></warning>
<para>The <literal>storage</literal> zpool should have been
created. This may be verified by using the &man.mount.8; and
@ -432,8 +442,8 @@ Filesystem 1K-blocks Used Avail Capacity Mounted on
/dev/ad0s1a 2026030 235240 1628708 13% /
devfs 1 1 0 100% /dev
/dev/ad0s1d 54098308 1032826 48737618 2% /usr
storage 17547008 0 17547008 0% /storage
storage/home 17547008 0 17547008 0% /home</screen>
storage 26320512 0 26320512 0% /storage
storage/home 26320512 0 26320512 0% /home</screen>
<para>This completes the <acronym>RAID</acronym>-Z
configuration. To get status updates about the file systems
@ -477,6 +487,7 @@ config:
raidz1 DEGRADED 0 0 0
da0 ONLINE 0 0 0
da1 OFFLINE 0 0 0
da2 ONLINE 0 0 0
errors: No known data errors</screen>
@ -509,6 +520,7 @@ config:
raidz1 ONLINE 0 0 0
da0 ONLINE 0 0 0
da1 ONLINE 0 0 0
da2 ONLINE 0 0 0
errors: No known data errors</screen>
@ -556,6 +568,7 @@ config:
raidz1 ONLINE 0 0 0
da0 ONLINE 0 0 0
da1 ONLINE 0 0 0
da2 ONLINE 0 0 0
errors: No known data errors</screen>