man/systemd-gpt-auto-generator.xml

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  10   Copyright 2013 Lennart Poettering
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  25 <refentry id="systemd-gpt-auto-generator">
  26
  27   <refentryinfo>
  28     <title>systemd-gpt-auto-generator</title>
  29     <productname>systemd</productname>
  30
  31     <authorgroup>
  32       <author>
  33         <contrib>Developer</contrib>
  34         <firstname>Lennart</firstname>
  35         <surname>Poettering</surname>
  36         <email>lennart@poettering.net</email>
  37       </author>
  38     </authorgroup>
  39   </refentryinfo>
  40
  41   <refmeta>
  42     <refentrytitle>systemd-gpt-auto-generator</refentrytitle>
  43     <manvolnum>8</manvolnum>
  44   </refmeta>
  45
  46   <refnamediv>
  47     <refname>systemd-gpt-auto-generator</refname>
  48     <refpurpose>Generator for automatically discovering
  49     and mounting root, <filename>/home</filename> and
  50     <filename>/srv</filename> partitions, as well as
  51     discovering and enabling swap partitions, based on GPT
  52     partition type GUIDs.</refpurpose>
  53   </refnamediv>
  54
  55   <refsynopsisdiv>
  56     <para><filename>&rootlibexecdir;/system-generators/systemd-gpt-auto-generator</filename></para>
  57   </refsynopsisdiv>
  58
  59   <refsect1>
  60     <title>Description</title>
  61
  62     <para><filename>systemd-gpt-auto-generator</filename> is a unit
  63     generator that automatically discovers root,
  64     <filename>/home</filename>, <filename>/srv</filename> and swap
  65     partitions and creates mount and swap units for them, based on the
  66     partition type GUIDs of GUID partition tables (GPT). It implements
  67     the <ulink
  68     url="http://www.freedesktop.org/wiki/Specifications/DiscoverablePartitionsSpec/">Discoverable
  69     Partitions Specification</ulink>. Note that this generator has no
  70     effect on non-GPT systems, or where the directories under the
  71     mount points are already non-empty. Also, on systems where the
  72     units are explicitly configured (for example, listed in
  73     <citerefentry
  74     project='man-pages'><refentrytitle>fstab</refentrytitle><manvolnum>5</manvolnum></citerefentry>),
  75     the units this generator creates are overriden, but additional
  76     automatic dependencies might be created.</para>
  77
  78     <para>This generator will only look for root partitions on the
  79     same physical disk the EFI System Partition (ESP) is located on.
  80     It will only look for the other partitions on the same physical
  81     disk the root file system is located on. These partitions will not
  82     be searched on systems where the root file system is distributed
  83     on multiple disks, for example via btrfs RAID.</para>
  84
  85     <para><filename>systemd-gpt-auto-generator</filename> is useful
  86     for centralizing file system configuration in the partition table
  87     and making manual configuration in <filename>/etc/fstab</filename>
  88     or suchlike unnecessary.</para>
  89
  90     <para>This generator looks for the partitions based on their
  91     partition type GUID. The following partition type GUIDs are
  92     identified:</para>
  93
  94     <table>
  95       <title>Partition Type GUIDs</title>
  96       <tgroup cols='3' align='left' colsep='1' rowsep='1'>
  97         <colspec colname="guid" />
  98         <colspec colname="name" />
  99         <colspec colname="explanation" />
 100         <thead>
 101           <row>
 102             <entry>Partition Type GUID</entry>
 103             <entry>Name</entry>
 104             <entry>Explanation</entry>
 105           </row>
 106         </thead>
 107         <tbody>
 108           <row>
 109             <entry>44479540-f297-41b2-9af7-d131d5f0458a</entry>
 110             <entry><filename>Root Partition (x86)</filename></entry>
 111             <entry>On 32-bit x86 systems, the first x86 root partition on the disk the EFI ESP is located on is mounted to the root directory <filename>/</filename>.</entry>
 112           </row>
 113           <row>
 114             <entry>4f68bce3-e8cd-4db1-96e7-fbcaf984b709</entry>
 115             <entry><filename>Root Partition (x86-64)</filename></entry>
 116             <entry>On 64-bit x86 systems, the first x86-64 root partition on the disk the EFI ESP is located on is mounted to the root directory <filename>/</filename>.</entry>
 117           </row>
 118           <row>
 119             <entry>69dad710-2ce4-4e3c-b16c-21a1d49abed3</entry>
 120             <entry><filename>Root Partition (32-bit ARM)</filename></entry>
 121             <entry>On 32-bit ARM systems, the first ARM root partition on the disk the EFI ESP is located on is mounted to the root directory <filename>/</filename>.</entry>
 122           </row>
 123           <row>
 124             <entry>b921b045-1df0-41c3-af44-4c6f280d3fae</entry>
 125             <entry><filename>Root Partition (64-bit ARM)</filename></entry>
 126             <entry>On 64-bit ARM systems, the first ARM root partition on the disk the EFI ESP is located on is mounted to the root directory <filename>/</filename>.</entry>
 127           </row>
 128           <row>
 129             <entry>933ac7e1-2eb4-4f13-b844-0e14e2aef915</entry>
 130             <entry>Home Partition</entry>
 131             <entry>The first home partition on the disk the root partition is located on is mounted to <filename>/home</filename>.</entry>
 132           </row>
 133           <row>
 134             <entry>3b8f8425-20e0-4f3b-907f-1a25a76f98e8</entry>
 135             <entry>Server Data Partition</entry>
 136             <entry>The first server data partition on the disk the root partition is located on is mounted to <filename>/srv</filename>.</entry>
 137           </row>
 138           <row>
 139             <entry>0657fd6d-a4ab-43c4-84e5-0933c84b4f4f</entry>
 140             <entry>Swap</entry>
 141             <entry>All swap partitions located on the disk the root partition is located on are enabled.</entry>
 142           </row>
 143         </tbody>
 144       </tgroup>
 145     </table>
 146
 147     <para>The <filename>/home</filename> and <filename>/srv</filename>
 148     partitions may be encrypted in LUKS format. In this case a device
 149     mapper device is set up under the names
 150     <filename>/dev/mapper/home</filename> and
 151     <filename>/dev/mapper/srv</filename>. Note that this might create
 152     conflicts if the same partition is listed in
 153     <filename>/etc/crypttab</filename> with a different device mapper
 154     device name.</para>
 155
 156     <para>Also note that
 157     <citerefentry><refentrytitle>systemd-efi-boot-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>
 158     will mount the EFI System Partition (ESP) to
 159     <filename>/boot</filename> if not otherwise mounted.</para>
 160
 161     <para>When using this generator in conjunction with btrfs file
 162     systems, make sure to set the correct default subvolumes on them,
 163     using <command>btrfs subvolume set-default</command>.</para>
 164
 165     <para><filename>systemd-gpt-auto-generator</filename> implements
 166     <citerefentry><refentrytitle>systemd.generator</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para>
 167   </refsect1>
 168
 169   <refsect1>
 170     <title>See Also</title>
 171     <para>
 172       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 173       <citerefentry><refentrytitle>systemd.mount</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 174       <citerefentry><refentrytitle>systemd.swap</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 175       <citerefentry><refentrytitle>systemd-fstab-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 176       <citerefentry><refentrytitle>systemd-efi-boot-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 177       <citerefentry><refentrytitle>systemd-cryptsetup@.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 178       <citerefentry project='die-net'><refentrytitle>cryptsetup</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 179       <citerefentry project='man-pages'><refentrytitle>fstab</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 180       <citerefentry project='man-pages'><refentrytitle>btrfs</refentrytitle><manvolnum>8</manvolnum></citerefentry>
 181     </para>
 182   </refsect1>
 183
 184 </refentry>