<?xml version="1.0" encoding="EUC-JP"?>
<!-- retain these comments for translator revision tracking -->
<!-- original version: 44026 -->

   <sect3 id="mdcfg">
   <title>ޥǥǥХ (եȥ 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>).
-->
ԥ塼ʣϡɥǥɥ饤֤<footnote><para>

ΤȤ򤤤СƱʪɥ饤֤ʬ䤷 MD ǥХۤǤޤ
ʤȤϤʤˤ⤢ޤ

</para></footnote>ʤ顢
ɥ饤֤Υѥեޥ󥹤θǡοΤ
<command>mdcfg</command> ѤǤޤ
η̤ <firstterm>ޥǥǥХ</firstterm>
(<firstterm>եȥ RAID</firstterm> ͭ̾) ȸƤӤޤ

</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.).
-->
MD ϴṲ̄Υǥˤѡƥ«ͤơ
<emphasis></emphasis> ǥХη˷礷ΤǤ
ΥǥХ̾Υѡƥ 
(: <command>partman</command> ǥեޥåȤǤ
ޥȥݥȤ˳Ƥ) Ʊͤ˻ѤǤޤ

</para><para>

<!--
What benefits this brings depends on the type of MD device you are
creating. Currently supported are:
-->
ɤʲä뤫ϡ MD ǥХμ˰¸ޤ
ߡʲ򥵥ݡȤƤޤ

<variablelist>
<varlistentry>

<term>RAID0</term><listitem><para>

<!--
Is mainly aimed at performance.  RAID0 splits all incoming 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 lose
<emphasis>everything</emphasis> (part of the information is still on
the healthy disk(s), the other part <emphasis>was</emphasis> on the
failed disk).
-->
RAID0 ϥѥեޥ󥹤˼򤪤Ƥޤ
RAID0 ϥǡ <firstterm>stripes</firstterm> ʬ䤷
˥ǥ쥤γƥǥʬۤޤ
ˤꡢɤ߼ꡦ񤭹ߤν®٤Ǥޤ
ǥΤ 1 Ĥ»顢
<emphasis>٤</emphasis>򼺤äƤޤޤ
(ΰʥǥˤޤ
¾ʬ<emphasis>»ǥˤ</emphasis>Ǥ)

</para><para>

<!--
The typical use for RAID0 is a partition for video editing.
-->
RAID0 ŵŪʻˡϱԽѤΥѡƥǤ

</para></listitem>
</varlistentry>
<varlistentry>

<term>RAID1</term><listitem><para>

<!--
Is suitable for setups where reliability is the first concern.  It
consists of several (usually two) equally-sized partitions where every
partition contains exactly the same data. This essentially 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.
-->
Ǥ硢RAID1 Ȥ褤Ǥ礦
ѡƥΤƱǡޤ褦ʡ
Ĥ (Ƥ 2 ) Υѡƥ󤫤ޤ
ܼŪ 3 ĤΤȤ̣ޤ
ޤǥ 1 Ĥ»硢Ĥäǥ˥ǡߥ顼Ĥޤ
ѲǽΰҤλѤǤޤ
(äΤˤϡRAID ǹǾΥѡƥ󥵥Ȥʤޤ)
 3 ˡǥΥեɤ߹ߤɥХ󥹤Ǥޤ
ˤꡢե륵ФΤ褦ʡ
񤭹ߤɤ߹ߤ٤⤯ʤ뷹Τ륵Ф
ѥեޥ󥹤Ǥޤ
</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.
-->
»ˡǤդͽǥ»ǥˡ
ǥ쥤ˤĤ뤳ȤǤޤ

</para></listitem>
</varlistentry>
<varlistentry>

<term>RAID5</term><listitem><para>

<!--
Is a good compromise between speed, reliability and data redundancy.
RAID5 splits all incoming data into stripes and distributes them
equally on all but one disk (similar to RAID0). Unlike RAID0, RAID5
also computes <firstterm>parity</firstterm> information, which gets
written on the remaining disk. The parity disk is not static (that
would be called RAID4), but is changing periodically, so the parity
information is distributed equally on all disks.  When one of the
disks fails, the missing part of information can be computed from
remaining data and its parity. RAID5 must consist of at least three
active partitions. Optionally you can have a spare disk in the array
which will take the place of the failed disk in the case of failure.
-->
RAID5 ®٤ȿǡξĹ򤦤ޤ路Ƥޤ
RAID5 ϥȥ饤פϤǡ򤹤٤ʬ䤷
1 İʳǥ (RAID0 Τ褦) ʬۤޤ
RAID0 Ȱ㤤RAID5  (ĤΥǥ˽񤫤Ƥ) 
<firstterm>ѥƥ</firstterm>׻ޤ
ѥƥǥŪ ( RAID4 ȸƤ) ǤϤޤ
(Ūѹ) ѥƥǥʬۤޤ
ǥξ㤷硢
μäʬϻĤäǥȤΥѥƥ׻ޤ
RAID5 ϾʤȤ 3 ĤΥƥ֤ʥѡƥ󤫤ޤ
ξ㤷ˡǤդǥǥ쥤θξ㤷ǥβս
ͽΥǥ򥻥åȤǤޤ

</para><para>

<!--
As you can see, RAID5 has a similar degree of reliability to RAID1
while achieving less redundancy. On the other hand, it might be a bit
slower on write operations than RAID0 due to computation of parity
information.
-->
狼Τ褦ˡRAID5  RAID1 ĹʤƱ٤οޤ
ѥƥ׻뤿ᡢRAID0 񤭹٤⤷ޤ

</para></listitem>
</varlistentry>
</variablelist>
<!--
To sum it up:
-->
ޤȤ

<informaltable>
<tgroup cols="5">
<thead>
<row>
  <entry></entry>
  <entry>ǥХǾ</entry>
  <entry>ͽǥХ</entry>
  <entry>ǥ»Ѥ뤫?</entry>
  <entry>Ѳǽΰ</entry>
</row>
</thead>

<tbody>
<row>
  <entry>RAID0</entry>
  <entry>2</entry>
  <entry></entry>
  <entry></entry>
  <entry>RAID ˤǾѡƥΥߥǥХ</entry>
</row>

<row>
  <entry>RAID1</entry>
  <entry>2</entry>
  <entry>Ǥ</entry>
  <entry></entry>
  <entry>RAID ˤǾѡƥΥ</entry>
</row>

<row>
  <entry>RAID5</entry>
  <entry>3</entry>
  <entry>Ǥ</entry>
  <entry></entry>
  <entry>
    RAID ˤǾѡƥΥ(ǥХ - 1)
  </entry>
</row>

</tbody></tgroup></informaltable>

</para><para>

<!--
If you want to know more about Software RAID, have a look
at <ulink url="&url-software-raid-howto;">Software RAID HOWTO</ulink>.
-->
եȥ RAID ˴ؤơäΤꤿ
<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>physical volume for
RAID</guimenuitem> </menuchoice>.)
-->
MD ǥХˤϡRAID ǻȤ
( <menuchoice><guimenu>ˡ:</guimenu> 
<guimenuitem>RAID ʪܥ塼</guimenuitem> </menuchoice>
򤷤ƽФƤ롢<guimenu>ѡƥ</guimenu> ˥塼
<command>partman</command> ǹԤޤ)

</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.
-->
MD ΥݡȤϡ󥹥ȡŪɲäޤ
root (<filename>/</filename>) ե륷ƥѤ MD Ѥʤ顢
RAID ٥֡ȥȤ߹碌ݤ˹ԤǤ礦
иѤ桼ˡ
Ĥꤷꥤ󥹥ȡ륹ƥåפ򥷥뤫ưǹԤäꤷơ
򤷤ư뤳ȤǤ뤫Τޤ

</para></warning><para>

<!--
Next, you should choose <guimenuitem>Configure software
RAID</guimenuitem> from the main <command>partman</command> menu.
(The menu will only appear after you mark at least one partition for
use as <guimenuitem>physical volume for RAID</guimenuitem>.)
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.
-->
˥ᥤ <command>partman</command> ˥塼 
<guimenuitem>եȥ RAID </guimenuitem> Ǥ
(Υ˥塼ϡʤȤѡƥҤȤ 
<guimenuitem>RAID ʪܥ塼</guimenuitem> 
Ȥƥޡʤɽޤ)
<command>mdcfg</command> κǽβ̤Ǥϡ
ñ <guimenu>MD ǥХκ</guimenu> 򤷤Ƥ
ݡȤ MD ǥХΥꥹȤ󶡤ޤ
椫 1  (: RAID1) 򤷤Ƥ
θ򤷤 MD ǥХ˰¸ޤ
</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.
-->
RAID0 ñǤѲǽ RAID ѡƥΰ󶡤ޤΤǡ
ñ MD ˤѡƥ򤷤Ƥ

</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.
-->
RAID1 ϾȥåǤ
ޤ MD ˤ륢ƥ֤ʥǥХο
ڥǥХοϤޤ
Ѳǽ RAID ѡƥΰ饢ƥ֤ΤΡ
˥ڥΤΤɬפޤ
򤷤ѡƥοۤϤϰפʤФʤޤ
ۤʤǤ
ְäư㤦Υѡƥ򤷤硢&d-i; ޤǡ
˿ʤޤޤ

</para></listitem>
<listitem><para>

<!--
RAID5 has a similar setup procedure as RAID1 with the exception that you
need to use at least <emphasis>three</emphasis> active partitions.
-->
RAID5 ǤϡʤȤ <emphasis>3 </emphasis>Υƥ֥ѡƥ
ѤɬפȤ㳰
RAID1 ƱͤΥåȥå׼³Ԥޤ

</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 the first partitions on
all three disks 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>).
-->
Ʊ˿ MD ĤȤϴ˲ǽǤ
㤨С3 Ĥ 200GB  MD ѥɥ饤֤äơ
ɤ 2 Ĥ 100GB ΥѡƥʬƤ硢
3 ĤΥɥ饤֤٤ƤκǽΥѡƥ RAID0 
(® 300GB ΥӥǥԽѡƥ) ǷǤ
¾ 3 ĤΥѡƥ (ƥ 2 𡢥ڥ 1 )  RAID1 
(<filename>/home</filename> Ѥ˿Ǥ 100GB Υѡƥ) ǷǤޤ

</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.
-->
ߤ̤ MD ǥХ򤷤ǡ
<guimenuitem>λ</guimenuitem> <command>mdcfg</command> Ȥ
<command>partman</command> ޤ
 MD ǥХ˥ե륷ƥ
ޥȥݥȤʤɤ̾°ꤷƤ

</para>
   </sect3>