svn commit: r43798 - head/en_US.ISO8859-1/books/handbook/disks
Warren Block
wblock at FreeBSD.org
Thu Feb 6 04:03:29 UTC 2014
Author: wblock
Date: Thu Feb 6 04:03:28 2014
New Revision: 43798
URL: http://svnweb.freebsd.org/changeset/doc/43798
Log:
Add a new section on growing disks. Modified version of patch submitted
with PR.
PR: docs/186377
Submitted by: Allan Jude <freebsd at allanjude.com>
Modified:
head/en_US.ISO8859-1/books/handbook/disks/chapter.xml
Modified: head/en_US.ISO8859-1/books/handbook/disks/chapter.xml
==============================================================================
--- head/en_US.ISO8859-1/books/handbook/disks/chapter.xml Thu Feb 6 01:58:10 2014 (r43797)
+++ head/en_US.ISO8859-1/books/handbook/disks/chapter.xml Thu Feb 6 04:03:28 2014 (r43798)
@@ -252,6 +252,154 @@
<screen>&prompt.root; <userinput>mount /newdisk</userinput></screen>
</sect1>
+ <sect1 xml:id="disks-growing">
+ <info>
+ <title>Resizing and Growing Disks</title>
+
+ <authorgroup>
+ <author>
+ <personname>
+ <firstname>Allan</firstname>
+ <surname>Jude</surname>
+ </personname>
+ <contrib>Originally contributed by </contrib>
+ </author>
+ </authorgroup>
+ </info>
+
+ <indexterm>
+ <primary>disks</primary>
+ <secondary>resizing</secondary>
+ </indexterm>
+
+ <para>A disk's capacity can increase without any changes to the
+ data already present. This happens commonly with virtual
+ machines, when the virtual disk turns out to be too small and is
+ enlarged. Sometimes a disk image is written to a
+ <acronym>USB</acronym> memory stick, but does not use the full
+ capacity. Here we describe how to resize or
+ <emphasis>grow</emphasis> disk contents to take advantage of
+ increased capacity.</para>
+
+ <para>Determine the device name of the disk to be resized by
+ inspecting <filename>/var/run/dmesg.boot</filename>. In this
+ example, there is only one <acronym>SATA</acronym> disk in the
+ system, so the drive will appear as
+ <filename>ada0</filename>.</para>
+
+ <indexterm><primary>partitions</primary></indexterm>
+ <indexterm>
+ <primary><command>gpart</command></primary>
+ </indexterm>
+
+ <para>List the partitions on the disk to see the current
+ configuration:</para>
+
+ <screen>&prompt.root; <command>gpart show <replaceable>ada0</replaceable></command>
+=> 34 83886013 ada0 GPT (48G) [CORRUPT]
+ 34 128 1 freebsd-boot (64k)
+ 162 79691648 2 freebsd-ufs (38G)
+ 79691810 4194236 3 freebsd-swap (2G)
+ 83886046 1 - free - (512B)</screen>
+
+ <note>
+ <para>If the disk was formatted with the <link
+ xlink:href="http://en.wikipedia.org/wiki/GUID_Partition_Table">
+ <acronym>GPT</acronym></link> partitioning scheme, it may show
+ as <quote>corrupted</quote> because the <acronym>GPT</acronym>
+ backup partition table is no longer at the end of the
+ drive. Fix the backup
+ partition table with
+ <command>gpart</command>:</para>
+
+ <screen>&prompt.root; <command>gpart recover <replaceable>ada0</replaceable></command>
+ada0 recovered</screen>
+ </note>
+
+ <para>Now the additional space on the disk is available for
+ use by a new partition, or an existing partition can be
+ expanded:</para>
+
+ <screen>&prompt.root; <command>gpart show <replaceable>ada0</replaceable></command>
+=> 34 102399933 ada0 GPT (48G)
+ 34 128 1 freebsd-boot (64k)
+ 162 79691648 2 freebsd-ufs (38G)
+ 79691810 4194236 3 freebsd-swap (2G)
+ 83886046 18513921 - free - (8.8G)</screen>
+
+ <para>Partitions can only be resized into contiguous free space.
+ Here, the last partition on the disk is the swap partition, but
+ the second partition is the one that needs to be resized. Swap
+ partitions only contain temporary data, so it can safely be
+ unmounted, deleted, and then recreated after resizing other
+ partitions.</para>
+
+ <screen>&prompt.root; <command>swapoff <replaceable>/dev/ada0p3</replaceable></command>
+&prompt.root; <command>gpart delete -i <replaceable>3</replaceable> <replaceable>ada0</replaceable></command>
+ada0p3 deleted
+&prompt.root; <command>gpart show <replaceable>ada0</replaceable></command>
+=> 34 102399933 ada0 GPT (48G)
+ 34 128 1 freebsd-boot (64k)
+ 162 79691648 2 freebsd-ufs (38G)
+ 79691810 22708157 - free - (10G)</screen>
+
+ <warning>
+ <para>There is risk of data loss when modifying the partition
+ table of a mounted file system. It is best to perform the
+ following steps on an unmounted file system while running from
+ a live <acronym>CD-ROM</acronym> or <acronym>USB</acronym>
+ device. However, if absolutely necessary, a mounted file
+ system can be resized after disabling GEOM safety
+ features:</para>
+
+ <screen>&prompt.root; <command>sysctl kern.geom.debugflags=16</command></screen>
+ </warning>
+
+ <para>Resize the partition, leaving room to recreate a swap
+ partition of the desired size. This only modifies the size of
+ the partition. The file system in the partition will be
+ expanded in a separate step.</para>
+
+ <screen>&prompt.root; <command>gpart resize -i <replaceable>2</replaceable> -a 4k -s <replaceable>47G</replaceable> <replaceable>ada0</replaceable></command>
+ada0p2 resized
+&prompt.root; <command>gpart show <replaceable>ada0</replaceable></command>
+=> 34 102399933 ada0 GPT (48G)
+ 34 128 1 freebsd-boot (64k)
+ 162 98566144 2 freebsd-ufs (47G)
+ 98566306 3833661 - free - (1.8G)</screen>
+
+ <para>Recreate the swap partition:</para>
+
+ <screen>&prompt.root; <command>gpart add -t freebsd-swap -a 4k <replaceable>ada0</replaceable></command>
+ada0p3 added
+&prompt.root; <command>gpart show <replaceable>ada0</replaceable></command>
+=> 34 102399933 ada0 GPT (48G)
+ 34 128 1 freebsd-boot (64k)
+ 162 98566144 2 freebsd-ufs (47G)
+ 98566306 3833661 3 freebsd-swap (1.8G)
+&prompt.root; <command>swapon <replaceable>/dev/ada0p3</replaceable></command></screen>
+
+ <para>Grow the <acronym>UFS</acronym> file system to use the new
+ capacity of the resized partition:</para>
+
+ <note>
+ <para>Growing a live <acronym>UFS</acronym> file system is only
+ possible in &os; 10.0-RELEASE and later. For earlier
+ versions, the file system must not be mounted.</para>
+ </note>
+
+ <screen>&prompt.root; <command>growfs <replaceable>/dev/ada0p2</replaceable></command>
+Device is mounted read-write; resizing will result in temporary write suspension for /.
+It's strongly recommended to make a backup before growing the file system.
+OK to grow file system on /dev/ada0p2, mounted on /, from 38GB to 47GB? [Yes/No] <userinput>Yes</userinput>
+super-block backups (for fsck -b #) at:
+ 80781312, 82063552, 83345792, 84628032, 85910272, 87192512, 88474752,
+ 89756992, 91039232, 92321472, 93603712, 94885952, 96168192, 97450432</screen>
+
+ <para>Both the partition and the file system on it have now been
+ resized to use the newly-available disk space.</para>
+ </sect1>
+
<sect1 xml:id="usb-disks">
<info>
<title>USB Storage Devices</title>
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