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diff --git a/fi/using-d-i/modules/mdcfg.xml b/fi/using-d-i/modules/mdcfg.xml deleted file mode 100644 index 04f76a6d4..000000000 --- a/fi/using-d-i/modules/mdcfg.xml +++ /dev/null @@ -1,222 +0,0 @@ -<!-- retain these comments for translator revision tracking --> -<!-- original version: 33725 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 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 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 (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. - -</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> -<varlistentry> - -<term>RAID5</term><listitem><para> - -Is a good compromise between speed, reliability and data redundancy. -RAID5 splits all incomming data into stripes and distributes them -equally on all but one disks (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. - -</para><para> - -As you can see, RAID5 has similar degree of reliability like RAID1 -while achieving less redundancy. On the other hand it might be a bit -slower on write operation than RAID0 due to computation of parity -information. - -</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> - -<row> - <entry>RAID5</entry> - <entry>3</entry> - <entry>optional</entry> - <entry>yes</entry> - <entry> - Size of the smallest partition multiplied by (number of devices in - RAID minus one) - </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>physical volume for -RAID</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 — 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> -<listitem><para> - -RAID5 has similar setup procedure as RAID1 with the exception that you -need to use at least <emphasis>three</emphasis> active partitions. - -</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> |