Date: Thu, 6 Feb 2014 04:03:29 +0000 (UTC) From: Warren Block <wblock@FreeBSD.org> To: doc-committers@freebsd.org, svn-doc-all@freebsd.org, svn-doc-head@freebsd.org Subject: svn commit: r43798 - head/en_US.ISO8859-1/books/handbook/disks Message-ID: <201402060403.s1643Tpe014318@svn.freebsd.org>
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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@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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