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+<!-- retain these comments for translator revision tracking -->
+<!-- original version: 22841 untranslated -->
+
+   <sect3 id="mdcfg">
+   <title>Configuring Multidisk Device (Software RAID)</title>
+<para>
+
+If you have more than one harddrive<footnote><para>
+
+To be honest, you can construct MD device even from partitions
+residing on single physical drive, but that won't bring you anything
+useful.
+
+</para></footnote> in your computer, you can use
+<command>mdcfg</command> to setup your drives for increased
+performance and/or better reliability of your data. The result is
+called <firstterm>Multidisk Device</firstterm> (or after its most
+famous variant <firstterm>software RAID</firstterm>).
+
+</para><para>
+
+MD is basically a bunch of partitions located on different disks and
+combined together to form a <emphasis>logical</emphasis> device. This
+device can then be used like an ordinary partition (i.e. in
+<command>partman</command> you can format it, assign a mountpoint,
+etc.).
+
+</para><para>
+
+The benefit you gain depends on a type of a MD device you are
+creating. Currently supported are:
+
+<variablelist>
+<varlistentry>
+
+<term>RAID0</term><listitem><para>
+
+Is mainly aimed at performance.  RAID0 splits all incomming data into
+<firstterm>stripes</firstterm> and distributes them equally over each
+disk in the array. This can increase the speed of read/write
+operations, but when one of the disks fails, you will loose
+<emphasis>everything</emphasis> (part of the information is still on
+the healthy disk(s), the other part <emphasis>was</emphasis> on the
+failed disk).
+
+</para><para>
+
+The typical use for RAID0 is a partition for video editing.
+
+</para></listitem>
+</varlistentry>
+<varlistentry>
+
+<term>RAID1</term><listitem><para>
+
+Is suitable for setups where reliability is the first concern.  It
+consists of several (usualy two) equaly sized partitions where every
+partition contains exactly the same data. This essentialy means three
+things.  First, if one of your disks fails, you still have the data
+mirrored on the remaining disks. Second, you can use only a fraction
+of the available capacity (more precisely, it is the size of the
+smallest partition in the RAID). Third, file reads are load balanced among
+the disks, which can improve performance on a server, such as a file
+server, that tends to be loaded with more disk reads than writes.
+
+</para><para>
+
+Optionally you can have a spare disk in the array which will take the
+place of the failed disk in the case of failure.
+
+</para></listitem>
+</varlistentry>
+</variablelist>
+
+To sum it up:
+
+<informaltable>
+<tgroup cols="5">
+<thead>
+<row>
+  <entry>Type</entry>
+  <entry>Minimum Devices</entry>
+  <entry>Spare Device</entry>
+  <entry>Survives disk failure?</entry>
+  <entry>Available Space</entry>
+</row>
+</thead>
+
+<tbody>
+<row>
+  <entry>RAID0</entry>
+  <entry>2</entry>
+  <entry>no</entry>
+  <entry>no</entry>
+  <entry>Size of the smallest partition multiplied by number of devices in RAID</entry>
+</row>
+
+<row>
+  <entry>RAID1</entry>
+  <entry>2</entry>
+  <entry>optional</entry>
+  <entry>yes</entry>
+  <entry>Size of the smallest partition in RAID</entry>
+</row>
+
+</tbody></tgroup></informaltable>
+
+</para><para>
+
+If you want to know the whole truth about Software RAID, have a look
+at <ulink url="&url-software-raid-howto;">Software RAID HOWTO</ulink>.
+
+</para><para>
+
+To create a MD device, you need to have the desired partitions it
+should consist of marked for use in a RAID.  (This is done in
+<command>partman</command> in the <guimenu>Partition
+settings</guimenu> menu where you should select <menuchoice>
+<guimenu>Use as:</guimenu> <guimenuitem>Use the partition as a RAID
+device</guimenuitem> </menuchoice>.)
+
+</para><warning><para>
+
+Support for MD is a relatively new addition to the installer.
+You may experience problems for some RAID levels and in combination
+with some bootloaders if you try to use MD for the root
+(<filename>/</filename>) filesystem. For experienced users, it may be
+possible to work around some of these problems by executing some
+configuration or installation steps manually from a shell.
+
+</para></warning><para>
+
+Next, you should choose <guimenuitem>Configure software
+RAID</guimenuitem> from the main <command>partman</command> menu.
+On the first screen of <command>mdcfg</command> simply select
+<guimenuitem>Create MD device</guimenuitem>. You will be presented with
+a list of supported types of MD devices, from which you should choose
+one (e.g. RAID1). What follows depends on the type of MD you selected.
+</para>
+
+<itemizedlist>
+<listitem><para>
+
+RAID0 is simple &mdash; you will be issued with the list of available
+RAID partitions and your only task is to select the partitions which
+will form the MD.
+
+</para></listitem>
+<listitem><para>
+
+RAID1 is a bit more tricky. First, you will be asked to enter the
+number of active devices and the number of spare devices which will
+form the MD. Next, you need to select from the list of available RAID
+partitions those that will be active and then those that will be
+spare. The count of selected partitions must be equal to the number
+provided few seconds ago. Don't worry. If you make a mistake and
+select different number of partitions, the &d-i; won't let you
+continue until you correct the issue.
+
+</para></listitem>
+</itemizedlist>
+
+<para>
+
+It is perfectly possible to have several types of MD at once. For
+example if you have three 200 GB hard drives dedicated to MD, each
+containing two 100 GB partitions, you can combine first partitions on
+all three disk into the RAID0 (fast 300 GB video editing partition)
+and use the other three partitions (2 active and 1 spare) for RAID1
+(quite reliable 100 GB partition for <filename>/home</filename>).
+
+</para><para>
+
+After you setup MD devices to your liking, you can
+<guimenuitem>Finish</guimenuitem> <command>mdcfg</command> to return
+back to the <command>partman</command> to create filesystems on your
+new MD devices and assign them the usual attributes like mountpoints.
+
+</para>
+   </sect3>