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<article>
  <articleinfo>
    <title>Formatting Media For Use With FreeBSD</title>

    <subtitle>A Tutorial</subtitle>

    <authorgroup>
      <author>
	<firstname>Doug</firstname>

	<surname>White</surname>

	<affiliation>
	  <address>
	    <email>dwhite@resnet.uoregon.edu</email>
	  </address>
	</affiliation>
      </author>
    </authorgroup>

    <pubdate>March 1997</pubdate>

    <abstract>
      <para>This document describes how to slice, partition, and
	format hard disk drives and similar media for use with
	FreeBSD.  The examples given have been tested under FreeBSD
	2.2 and should work for other releases.  The text has been updated
	for FreeBSD version 4.</para>
    </abstract>
  </articleinfo>

  <sect1>
    <title>Introduction & Definitions</title>

    <sect2>
      <title>Overview</title>

      <para>Successfully adding disks to an existing system is the
	mark of an experienced system administrator.  Slicing,
	partitioning, and adding disks requires a careful dance of
	proper command and name syntax.  One slipped finger and an
	entire disk could disappear in seconds.  This document is
	written in an attempt to simplify this process and avoid
	accidents.  Thankfully, enhancements to existing tools
	(notably sysinstall) have greatly improved this process in
	recent releases of FreeBSD.</para>

      <para>There are two possible modes of disk formatting:</para>

      <itemizedlist> 
	<listitem>
	  <para><firstterm>compatibility mode</firstterm>: Arranging a
	    disk so that it has a slice table for use with other
	    operating systems.</para>
	</listitem>

	<listitem>
	  <para><firstterm>dedicated mode</firstterm>, sometimes called
	    <firstterm>dangerously dedicated mode</firstterm>: Formatting a disk
	    with no slice table.  This makes the process of adding disks easier,
	    however non-FreeBSD operating systems may not accept the disk.  The
	    term <emphasis>dangerously</emphasis> refers to the danger that the
	    system may not recognize a disk formatted in this manner.</para>
	    </listitem> </itemizedlist>

      <para>For most cases, dedicated mode is the easiest to set up
	and use in existing systems, as a new disk is usually
	dedicated entirely to FreeBSD.  However, compatibility mode
	insures optimum interoperability with future installations at
	a cost of increased complexity.</para>

      <para>In addition to selecting the mode, two methods of slicing
	the disk are available.  One is using the system installation
	tool <command>/stand/sysinstall</command>.  2.1.7-RELEASE and
	later versions of <command>sysinstall</command> contain code
	to ease setup of disks during normal system operation, mainly
	allowing access to the Label and Partition editors and a Write
	feature which will update just the selected disk and slice
	without affecting other disks.  The other method is running
	the tools manually from a root command line.  For 
	dedicated mode, only three or four commands are involved while
	<command>sysinstall</command> requires some
	manipulation.</para>
    </sect2>

    <sect2>
      <title>Definitions</title>

      <para>Unix disk management over the centuries has invented many
	new definitions for old words.  The following glossary covers
	the definitions used in this document and (hopefully) for
	FreeBSD in general.</para>

<!-- I'm tempted to use GLOSSARY here but will resort to a list for
now. -->

      <itemizedlist>
	<listitem>
	  <para>compatibility mode:  Arranging a disk so that it has a
	    slice table for use with other operating systems.  Oppose
	    dedicated mode.</para>
	</listitem>

	<listitem>
	  <para>(dangerously) dedicated mode:  Formatting a disk with no
	    slice table.  This makes the process of adding disks
	    easier, however non-FreeBSD operating systems may not
	    accept the disk.  Oppose compatibility mode.</para>
	</listitem>

	<listitem>
	  <para>disk:   A circular disc,  covered with magnetic or
	    similarly manipulable material, spun by a motor under a
	    head.  Data is stored on the disk by changing the pattern
	    of magnetism on the disc, which can be later read.  Hard
	    disks, CDROMs, Magneto-optical,and Zip/Jaz removables are
	    examples of disks.</para>
	</listitem>

	<listitem>
	  <para>slice: A division of a disk.  Up to four slices are
	    permitted on one disk in the PC standard.  Slices are
	    composed of contiguous sectors.  Slices are recorded in a
	    <quote>slice table</quote> used by the system BIOS to
	    locate bootable partitions.  The slice table is usually
	    called the <quote>partition table</quote> in DOS parlance.  Maintained by
	    the fdisk utility.</para>
	</listitem>

	<listitem>
	  <para>partition: A division of a slice.  Usually used in
	    reference to divisions of the FreeBSD slice of a disk.
	    Each filesystem and swap area on a disk resides in a
	    partition.  Maintained using the disklabel utility.</para>
	</listitem>
	
	<listitem>
	  <para>sector:  Smallest subdivision of a disk.  One sector
	    usually represents 512 bytes of data.</para>
	</listitem>
      </itemizedlist>
    </sect2>

    <sect2>
      <title>Warnings & Pitfalls</title>

      <para>Building disks is not something to take lightly.  It is
	quite possible to destroy the contents of other disks in your
	system if the proper precautions are not taken.</para>

      <para><emphasis>Check your work carefully.</emphasis>  It is very simple
	to destroy the incorrect disk when working with these
	commands.  When in doubt consult the kernel boot output for
	the proper device.</para>

      <para>Needless to say, we are not responsible for any damage to
	any data or hardware that you may experience.  You work at
	your own risk!</para>
    </sect2>

    <sect2>
      <title>Zip, Jaz, and Other Removables</title>

      <para>Removable disks can be formatted in the same way as normal
	hard disks.  It is essential to have the disk drive connected
	to the system and a disk placed in the drive during startup,
	so the kernel can determine the drive's geometry.  Check the
	<command>dmesg</command> output and make sure your device and
	the disk's size is listed.  If the kernel reports 

	<informalexample>
	  <screen>Can't get the size</screen>
	</informalexample>

	then the disk was not in the drive.  In this case, you will
	need to restart the machine before attempting to format
	disks.</para>
    </sect2>
  </sect1>

  <sect1>
    <title>Formatting Disks in Dedicated Mode</title>

    <sect2>
      <title>Introduction</title>

      <para>This section details how to make disks that are totally
	dedicated to FreeBSD.  Remember, dedicated mode disks sometimes
	cannot be booted by the PC architecture.</para>
    </sect2>

    <sect2>
      <title>Making Dedicated Mode Disks using Sysinstall</title>

      <para><command>/stand/sysinstall</command>, the system
	installation utility, has been expanded in recent versions to
	make the process of dividing disks properly a less tiring
	affair.  The fdisk and disklabel editors built into sysinstall
	are GUI tools that remove much of the confusion from slicing
	disks.  For FreeBSD versions 2.1.7 and later, this is perhaps
	the simplest way to slice disks.</para>

      <procedure>
	<step>
	  <para>Start sysinstall as root by typing 

	    <informalexample>
	      <screen>&prompt.root; <userinput>/stand/sysinstall</userinput></screen>
	    </informalexample> 

	    from the command prompt.</para>
	</step>

	<step>
	  <para>Select <command>Index</command>.</para>
	</step>

	<step>
	  <para>Select <command>Partition</command>.</para>
	</step>

	<step>
	  <para>Select the disk to edit with arrow keys and
	    <keycap>SPACE</keycap>.</para>
	</step>

	<step>
	  <para>If you are using this entire disk for FreeBSD, select
	    <command>A</command>.</para>
	</step> 

	<step>
	  <para>When asked: 

	    <informalexample>
	      <screen>Do you want to do this with a true partition entry so as to remain
cooperative with any future possible operating systems on the
drive(s)?</screen>
	    </informalexample>

	    answer <command>No</command>.</para>
	</step>

	<step>
	  <para>When asked if you still want to do this, answer
	    <command>Yes</command>.</para>
	</step> 

	<step>
	  <para>Select <command>Write</command>.</para>
	</step>

	<step>
	  <para>When warned about writing on installed systems, answer
	    <command>Yes</command>.</para>
	</step> 

	<step>
	  <para><command>Quit</command>the FDISK Editor and
	    <keycap>ESCAPE</keycap> back to the Index menu.</para>
	</step>

	<step>
	  <para>Select <command>Label</command> from the Index
	    menu.</para>
	</step>

	<step>
	  <para>Label as desired.  For a single partition, enter
	    <command>C</command> to Create a partition, accept the
	    default size, partition type Filesystem, and a mountpoint
	    (which is not used).</para>
	</step> 

	<step>
	  <para>Enter <command>W</command> when done and confirm to
	    continue.  The filesystem will be newfs'd for you, unless
	    you select otherwise (for new partitions you will want to
	    do this!).  You will get the error: 

	    <informalexample>
	      <screen>Error mounting /mnt/dev/ad2s1e on /mnt/blah : No such file or directory</screen>
	    </informalexample>

	    Ignore.</para>
	</step>

	<step>
	  <para>Exit out by repeatedly pressing
	    <keycap>ESCAPE</keycap>.</para>
	</step>
      </procedure>
    </sect2>

    <sect2>
      <title>Making Dedicated Mode Disks Using the Command Line</title>

      <para>Execute the following commands, replacing <devicename>ad2</devicename> with the
	disk name.</para>

      <informalexample>
	<screen>&prompt.root; <userinput>dd if=/dev/zero of=/dev/ad2 count=2</userinput>
&prompt.root; <userinput>disklabel /dev/ad2 | disklabel -B -R -r ad2 /dev/stdin</userinput>
<lineannotation>We only want one partition, so using slice 'c' should be fine:</lineannotation>
&prompt.root; <userinput>newfs /dev/ad2c</userinput></screen>
      </informalexample>

      <para>If you need to edit the disklabel to create multiple
	partitions (such as swap), use the following: </para>
        
      <informalexample>
	<screen>&prompt.root; <userinput>dd if=/dev/zero of=/dev/ad2 count=2</userinput>
&prompt.root; <userinput>disklabel /dev/ad2 > /tmp/label</userinput>
<lineannotation>Edit disklabel to add partitions:</lineannotation>
&prompt.root; <userinput>vi /tmp/label</userinput>
&prompt.root; <userinput>disklabel -B -R -r ad2 /tmp/label</userinput>
<lineannotation>newfs partitions appropriately</lineannotation></screen>
      </informalexample>

      <para>Your disk is now ready for use.</para>
    </sect2>
  </sect1>

  <sect1>
    <title>Making Compatibility Mode Disks</title>

    <sect2>
      <title>Introduction</title>

      <para>The command line is the easiest way to make dedicated
	disks, and the worst way to make compatibility disks.  The
	command-line <command>fdisk</command> utility requires higher math skills and an
	in-depth understanding of the slice table, which is more than
	most people want to deal with.  Use sysinstall for
	compatibility disks, as described below.</para>
    </sect2>

    <sect2>
      <title>Making Compatibility Mode Disks Using Sysinstall</title>

      <procedure>
	<step>
	  <para>Start sysinstall as root by typing 

	    <informalexample>
	      <screen>&prompt.root; <userinput>/stand/sysinstall</userinput></screen>
	    </informalexample> 

	    from the command prompt.</para>
	</step>

	<step>
	  <para>Select <command>Index</command>.</para>
	</step>

	<step>
	  <para>Select <command>Partition</command>.</para>
	</step>

	<step>
	  <para>Select the disk to edit with arrow keys and
	    <keycap>SPACE</keycap>.</para>
	</step>

	<step>
	  <para>If you are using this entire disk for FreeBSD, select
	    <command>A</command>.</para>
	</step> 

	<step>
	  <para>When asked: 

	    <informalexample>
	      <screen>Do you want to do this with a true partition entry so as to remain
cooperative with any future possible operating systems on the
drive(s)?</screen>
	    </informalexample>

	    answer <command>yes</command>.</para>
	</step>

	<step>
	  <para>Select <command>Write</command>.</para>
	</step>

	<step>
	  <para>When asked to install the boot manager, select None
	    with <keycap>SPACE</keycap> then hit
	    <keycap>ENTER</keycap> for OK.</para>
	</step>

	<step>
	  <para><command>Quit</command> the FDISK Editor.</para>
	</step>

	<step>
	  <para>You will be asked about the boot manager, select
	    <command>None</command> again. </para>
	</step> 

	<step>
	  <para>Select <command>Label</command> from the Index
	    menu.</para>
	</step>  

	<step>
	  <para>Label as desired.  For a single partition, accept the
	    default size, type filesystem, and a mountpoint (which
	    is not used).</para>
	</step> 

	<step>
	  <para>The filesystem will be newfs'd for you, unless you
	    select otherwise (for new partitions you will want to do
	    this!).  You will get the error:

	    <informalexample>
	      <screen>Error mounting /mnt/dev/ad2s1e on /mnt/blah : No such file or directory</screen> 
	    </informalexample>

	    Ignore.</para>
	</step>

	<step>
	  <para>Exit out by repeatedly pressing
	    <keycap>ESCAPE</keycap>.</para>
	</step>
      </procedure>

      <para>Your new disk is now ready for use.</para>
    </sect2>
  </sect1>

  <sect1>
    <title>Other Disk Operations</title>

    <sect2>
      <title>Adding Swap Space</title>

      <para>As a system grows, its need for swap space can also grow.
	Although adding swap space to existing disks is very
	difficult, a new disk can be partitioned with additional swap
	space.</para>

      <para>To add swap space when adding a disk to a system:</para>

      <procedure>
	<step>
	  <para>When partitioning the disk, edit the disklabel and
	    allocate the amount of swap space to add in partition `b'
	    and the remainder in another partition, such as `a' or
	    `e'.  The size is given in 512 byte blocks.</para>
	</step>

	<step>
	  <para>When newfsing the drive, do NOT newfs the `c'
	    partition.  Instead, newfs the partition where the
	    non-swap space lies.</para>
	</step> 

	<step>
	  <para>Add an entry to <filename>/etc/fstab</filename> as
	    follows:</para>

	  <informalexample>
	    <programlisting>/dev/ad0b                       none            swap    sw 0 0
	    </programlisting>
	  </informalexample>
	  
	  <para>Change <filename>/dev/ad0b</filename> to the device of the newly added
	    space.</para>
	</step>

	<step>
	  <para>To make the new space immediately available, use the
	    <command>swapon</command> command.

	    <informalexample>
	      <screen>&prompt.root; <userinput>swapon /dev/da0b</userinput>
swapon:  added /dev/da0b as swap space</screen>
	    </informalexample>
	  </para>
	</step>
      </procedure>
    </sect2>

    <sect2>
      <title>Copying the Contents of Disks</title>
<!-- Should have specific tag -->
      
      <para>Submitted By:  Renaud Waldura
	(<email>renaud@softway.com</email>) </para>

      <para>To move file from your original base disk to the fresh new
	one, do:

	<informalexample>
	  <screen>&prompt.root; <userinput>mount /dev/ad2 /mnt</userinput>
&prompt.root; <userinput>pax -r -w -p e /usr/home /mnt</userinput>
&prompt.root; <userinput>umount /mnt</userinput>
&prompt.root; <userinput>rm -rf /usr/home/*</userinput>
&prompt.root; <userinput>mount /dev/ad2 /usr/home</userinput></screen>
	</informalexample>
      </para>
    </sect2>

    <sect2>
      <title>Creating Striped Disks using CCD</title>

      <para>Commands Submitted By: Stan Brown
	(<email>stanb@awod.com</email>) </para>

      <para>The Concatenated Disk Driver, or CCD, allows you to treat
	several identical disks as a single disk.  Striping can result
	in increased disk performance by distributing reads and writes
	across the disks.  See the &man.ccd.4; and &man.ccdconfig.8;
	man pages or the <ulink
	  URL="http://stampede.cs.berkeley.edu/ccd/">CCD
	  Homepage</ulink> for further details.</para>

      <para>You no longer need to build a special kernel to run ccd.  When you
	run <command>ccdconfig</command>, it will load the KLD for you if the
	kernel does not contain CCD support.</para>

      <para>You build CCDs on disk partitions of type
	<emphasis>4.2BSD</emphasis>.  If you want to use the entire disk, you
	still need to create a new partition.  For example, <userinput>disklabel
	-e</userinput> might show:</para>

      <informalexample>
	<screen>#        size   offset    fstype   [fsize bsize bps/cpg]
  c: 60074784        0    unused        0     0     0   # (Cyl.    0 - 59597)</screen>
      </informalexample>

      <para>You should not use partition <emphasis>c</emphasis> for the CCD,
      since it is of type <emphasis>unused</emphasis>.  Instead, create a new
      partition of exactly the same size, but with type
      <emphasis>4.2BSD</emphasis>:</para>

      <informalexample>
	<screen>#        size   offset    fstype   [fsize bsize bps/cpg]
  c: 60074784        0    unused        0     0     0   # (Cyl.    0 - 59597)
<userinput>   e: 60074784        0    4.2BSD        0     0     0   # (Cyl.    0 - 59597)</userinput></screen>
      </informalexample>

	<para>To create a new CCD, execute the following commands.  This
	describes how to add three disks together; simply add or remove devices
	as necessary.  Remember that the disks to be striped must be
	<emphasis>identical.</emphasis></para>

      <informalexample>
	<screen>&prompt.root; <userinput>cd /dev ; sh MAKDEV ccd0</userinput>

&prompt.root; <userinput>disklabel -r -w da0 auto</userinput>
&prompt.root; <userinput>disklabel -r -w da1 auto</userinput>
&prompt.root; <userinput>disklabel -r -w da2 auto</userinput>

&prompt.root; <userinput>disklabel -e da0</userinput>
<lineannotation>Add partition e with type 4.2BSD</lineannotation>
&prompt.root; <userinput>disklabel -e da1</userinput>
<lineannotation>Add partition e with type 4.2BSD</lineannotation>
&prompt.root; <userinput>disklabel -e da2</userinput>
<lineannotation>Add partition e with type 4.2BSD</lineannotation>

&prompt.root; <userinput>ccdconfig ccd0 273 0 /dev/da0e /dev/da1e /dev/da2e</userinput>

&prompt.root; <userinput>newfs /dev/ccd0c</userinput></screen>
      </informalexample>

      <para>The value 273 is the stripe size.  This is the number of disk
      sectors (of 512 bytes each) in each block of data on the CCD.  It should
      be at least 128 kB, and it should not be not be a power of 2.</para>

      <para>Now you can mount and use your CCD by referencing device
	<filename>/dev/ccd0c</filename>.</para>

      <para>A more powerful and flexible alternative to CCD is Vinum.  See the
        <ulink URL="http://www.vinumvm.org/">Vinum Project home page</ulink>
        for further details.</para>
    </sect2>
  </sect1>

  <sect1>
    <title>Credits</title>

    <para>The author would like to thank the following individuals for
      their contributions to this project:</para>

    <itemizedlist>
      <listitem>
	<para>Darryl Okahata
	  (<email>darrylo@hpnmhjw.sr.hp.com</email>) for his simple
	  dedicated mode setup documentation which I have used
	  repeatedly on FreeBSD-questions.</para>
      </listitem>

      <listitem>
	<para>&a.jkh; for making sysinstall useful for this type of task.
	  </para>
      </listitem>

      <listitem>
	<para>John Fieber (<email>jfieber@indiana.edu</email>) for
	  making information and examples of the DocBook DTD on which
	  this document is based.</para>
      </listitem>

      <listitem>
	<para>&a.grog; for checking my work and pointing out inaccuracies,
	  as well as miscellaneous support.</para>
      </listitem>
    </itemizedlist>
  </sect1>
</article>
