source: postlfs/filesystems/mdadm.xml@ b9d5573a

<?xml version="1.0" encoding="ISO-8859-1"?>
<!DOCTYPE sect1 PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
   "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
  <!ENTITY % general-entities SYSTEM "../../general.ent">
  %general-entities;

  <!ENTITY mdadm-download-http "&kernel-dl;/linux/utils/raid/mdadm/mdadm-&mdadm-version;.tar.xz">
  <!ENTITY mdadm-download-ftp " ">
  <!ENTITY mdadm-md5sum        "51bf3651bd73a06c413a2f964f299598">
  <!ENTITY mdadm-size          "432 KB">
  <!ENTITY mdadm-buildsize     "4.9 MB (10 MB with tests)">
  <!ENTITY mdadm-time          "0.1 SBU (tests take about an hour, only partially processor dependent)">
]>

<sect1 id="mdadm" xreflabel="mdadm-&mdadm-version;">
  <?dbhtml filename="mdadm.html"?>

  <sect1info>
    <othername>$LastChangedBy$</othername>
    <date>$Date$</date>
  </sect1info>

  <title>mdadm-&mdadm-version;</title>

  <indexterm zone="mdadm">
    <primary sortas="a-mdadm">mdadm</primary>
  </indexterm>

  <sect2 role="package">
    <title>Introduction to mdadm</title>

    <para>
      The <application>mdadm</application> package contains administration
      tools for software RAID.
    </para>

    &lfs10_checked;

    <bridgehead renderas="sect3">Package Information</bridgehead>
    <itemizedlist spacing="compact">
      <listitem>
        <para>
          Download (HTTP): <ulink url="&mdadm-download-http;"/>
        </para>
      </listitem>
      <listitem>
        <para>
          Download (FTP): <ulink url="&mdadm-download-ftp;"/>
        </para>
      </listitem>
      <listitem>
        <para>
          Download MD5 sum: &mdadm-md5sum;
        </para>
      </listitem>
      <listitem>
        <para>
          Download size: &mdadm-size;
        </para>
      </listitem>
      <listitem>
        <para>
          Estimated disk space required: &mdadm-buildsize;
        </para>
      </listitem>
      <listitem>
        <para>
          Estimated build time: &mdadm-time;
        </para>
      </listitem>
    </itemizedlist>

    <bridgehead renderas="sect3">mdadm Dependencies</bridgehead>

    <bridgehead renderas="sect4">Optional</bridgehead>
    <para role="optional">
      A <xref linkend="server-mail"/>
    </para>
    <!-- Contains -DSendmail=/usr/sbin/sendmail in the build procedure -->

    <para condition="html" role="usernotes">User Notes:
    <ulink url="&blfs-wiki;/mdadm"/></para>
    <caution>
      <para>
        Kernel versions in series 4.1 through 4.4.1 have a broken RAID
        implementation. Use a kernel with version at or above 4.4.2.
      </para>
    </caution>

  </sect2>

  <sect2 role="kernel" id='mdadm-kernel'>
    <title>Kernel Configuration</title>

    <para>
      Enable the following options in the kernel configuration
      and recompile the kernel, if necessary.  Only the RAID types desired
      are required.
    </para>

<screen><literal>Device Drivers ---&gt;
  [*] Multiple devices driver support (RAID and LVM) ---&gt; [CONFIG_MD]
    &lt;*&gt; RAID support                                      [CONFIG_BLK_DEV_MD]
    [*]   Autodetect RAID arrays during kernel boot       [CONFIG_MD_AUTODETECT]
    &lt;*/M&gt;  Linear (append) mode                           [CONFIG_MD_LINEAR]
    &lt;*/M&gt;  RAID-0 (striping) mode                         [CONFIG_MD_RAID0]
    &lt;*/M&gt;  RAID-1 (mirroring) mode                        [CONFIG_MD_RAID1]
    &lt;*/M&gt;  RAID-10 (mirrored striping) mode               [CONFIG_MD_RAID10]
    &lt;*/M&gt;  RAID-4/RAID-5/RAID-6 mode                      [CONFIG_MD_RAID456]</literal></screen>

    <indexterm zone="mdadm mdadm-kernel">
      <primary sortas="d-mdadm">mdadm</primary>
    </indexterm>

  </sect2>

  <sect2 role="installation">
    <title>Installation of mdadm</title>

    <para>
      Fix a build error introduced by gcc-7.1:
    </para>

<screen><userinput>sed 's@-Werror@@' -i Makefile</userinput></screen>

    <para>
      Build <application>mdadm</application> by running the following
      command:
    </para>

<screen><userinput>make</userinput></screen>

    <para>
      If you wish to run the tests, ensure that your kernel supports RAID
      and that a version of mdadm is not already running.  As many as 9 out
      of 124 tests may fail.
    </para>

    <caution>
      <para>
        The tests edit values in /proc and run tests on software raid devices.
        They shouldn't be run on systems with active software RAID devices.
      </para>
    </caution>

    <para>
      Run the tests as the <systemitem class="username">root</systemitem> user:
    </para>

<screen role="root"
        remap="test"><userinput>./test --keep-going --logdir=test-logs --save-logs</userinput></screen>

    <para>
      Now, as the <systemitem class="username">root</systemitem> user:
    </para>

<screen role="root"><userinput>make install</userinput></screen>

  </sect2>

  <sect2 role="commands">
    <title>Command Explanations</title>

    <para>
      <command>make everything</command>: This optional target creates extra
      programs, particularly a statically-linked version of
      <command>mdadm</command> and also versions of
      <command>mdassemble</command>. These all need to be manually installed.
    </para>

    <para>
      <parameter>--keep-going</parameter>: Run the tests to the end, even if one
      or more tests fail.
    </para>

    <para>
      <parameter>--logdir=test-logs</parameter>: Defines the directory
      where test logs are saved.
    </para>

    <para>
      <parameter>--save-logs</parameter>:
      Instructs the test suite to save the logs.
    </para>

    <para>
      <option>--tests=<replaceable>&lt;test1,test2,...&gt;</replaceable></option>:
      Optional comma separated list of tests to be executed
      (all tests, if this option is not passed).
    </para>

  </sect2>


  <sect2 role="content">
    <title>Contents</title>

    <segmentedlist>
      <segtitle>Installed Programs</segtitle>
      <segtitle>Installed Libraries</segtitle>
      <segtitle>Installed Directory</segtitle>

      <seglistitem>
        <seg>mdadm, mdmon and optionally mdassemble</seg>
        <seg>None</seg>
        <seg>None</seg>
      </seglistitem>
    </segmentedlist>

    <variablelist>
      <bridgehead renderas="sect3">Short Descriptions</bridgehead>
      <?dbfo list-presentation="list"?>
      <?dbhtml list-presentation="table"?>

      <varlistentry id="mdadm-prog">
        <term><command>mdadm</command></term>
        <listitem>
          <para>
            manages MD devices aka Linux Software RAID.
          </para>
          <indexterm zone="mdadm mdadm-prog">
            <primary sortas="b-mdadm-prog">mdadm</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="mdmon">
        <term><command>mdmon</command></term>
        <listitem>
          <para>
            monitors MD external metadata arrays.
          </para>
          <indexterm zone="mdadm mdmon">
            <primary sortas="b-mdmon">mdmon</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="mdassemble">
        <term><command>mdassemble</command></term>
        <listitem>
          <para>
            is a tiny program that can be used to assemble MD devices
            inside an initial ramdisk (initrd) or initramfs.
          </para>
          <indexterm zone="mdadm mdassemble">
            <primary sortas="b-mdassemble">mdassemble</primary>
          </indexterm>
        </listitem>
      </varlistentry>

    </variablelist>

  </sect2>

</sect1>