man/systemd-gpt-auto-generator.xml

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   9   Copyright 2013 Lennart Poettering
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  24 <refentry id="systemd-gpt-auto-generator">
  25
  26   <refentryinfo>
  27     <title>systemd-gpt-auto-generator</title>
  28     <productname>systemd</productname>
  29
  30     <authorgroup>
  31       <author>
  32         <contrib>Developer</contrib>
  33         <firstname>Lennart</firstname>
  34         <surname>Poettering</surname>
  35         <email>lennart@poettering.net</email>
  36       </author>
  37     </authorgroup>
  38   </refentryinfo>
  39
  40   <refmeta>
  41     <refentrytitle>systemd-gpt-auto-generator</refentrytitle>
  42     <manvolnum>8</manvolnum>
  43   </refmeta>
  44
  45   <refnamediv>
  46     <refname>systemd-gpt-auto-generator</refname>
  47     <refpurpose>Generator for automatically discovering
  48     and mounting root, <filename>/home</filename> and
  49     <filename>/srv</filename> partitions, as well as
  50     discovering and enabling swap partitions, based on GPT
  51     partition type GUIDs.</refpurpose>
  52   </refnamediv>
  53
  54   <refsynopsisdiv>
  55     <para><filename>/usr/lib/systemd/system-generators/systemd-gpt-auto-generator</filename></para>
  56   </refsynopsisdiv>
  57
  58   <refsect1>
  59     <title>Description</title>
  60
  61     <para><filename>systemd-gpt-auto-generator</filename> is a unit
  62     generator that automatically discovers root,
  63     <filename>/home</filename>, <filename>/srv</filename> and swap
  64     partitions and creates mount and swap units for them, based on the
  65     partition type GUIDs of GUID partition tables (GPT). It implements
  66     the <ulink
  67     url="https://www.freedesktop.org/wiki/Specifications/DiscoverablePartitionsSpec/">Discoverable
  68     Partitions Specification</ulink>. Note that this generator has no
  69     effect on non-GPT systems, or where the directories under the
  70     mount points are already non-empty. Also, on systems where the
  71     units are explicitly configured (for example, listed in
  72     <citerefentry
  73     project='man-pages'><refentrytitle>fstab</refentrytitle><manvolnum>5</manvolnum></citerefentry>),
  74     the units this generator creates are overridden, but additional
  75     implicit dependencies might be created.</para>
  76
  77     <para>This generator will only look for root partitions on the
  78     same physical disk the EFI System Partition (ESP) is located on.
  79     It will only look for the other partitions on the same physical
  80     disk the root file system is located on. These partitions will not
  81     be searched on systems where the root file system is distributed
  82     on multiple disks, for example via btrfs RAID.</para>
  83
  84     <para><filename>systemd-gpt-auto-generator</filename> is useful
  85     for centralizing file system configuration in the partition table
  86     and making manual configuration in <filename>/etc/fstab</filename>
  87     or suchlike unnecessary.</para>
  88
  89     <para>This generator looks for the partitions based on their
  90     partition type GUID. The following partition type GUIDs are
  91     identified:</para>
  92
  93     <table>
  94       <title>Partition Type GUIDs</title>
  95       <tgroup cols='3' align='left' colsep='1' rowsep='1'>
  96         <colspec colname="guid" />
  97         <colspec colname="name" />
  98         <colspec colname="explanation" />
  99         <thead>
 100           <row>
 101             <entry>Partition Type GUID</entry>
 102             <entry>Name</entry>
 103             <entry>Explanation</entry>
 104           </row>
 105         </thead>
 106         <tbody>
 107           <row>
 108             <entry>44479540-f297-41b2-9af7-d131d5f0458a</entry>
 109             <entry><filename>Root Partition (x86)</filename></entry>
 110             <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>
 111           </row>
 112           <row>
 113             <entry>4f68bce3-e8cd-4db1-96e7-fbcaf984b709</entry>
 114             <entry><filename>Root Partition (x86-64)</filename></entry>
 115             <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>
 116           </row>
 117           <row>
 118             <entry>69dad710-2ce4-4e3c-b16c-21a1d49abed3</entry>
 119             <entry><filename>Root Partition (32-bit ARM)</filename></entry>
 120             <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>
 121           </row>
 122           <row>
 123             <entry>b921b045-1df0-41c3-af44-4c6f280d3fae</entry>
 124             <entry><filename>Root Partition (64-bit ARM)</filename></entry>
 125             <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>
 126           </row>
 127           <row>
 128             <entry>993d8d3d-f80e-4225-855a-9daf8ed7ea97</entry>
 129             <entry><filename>Root Partition (Itanium/IA-64)</filename></entry>
 130             <entry>On Itanium systems, the first Itanium root partition on the disk the EFI ESP is located on is mounted to the root directory <filename>/</filename>.</entry>
 131           </row>
 132           <row>
 133             <entry>933ac7e1-2eb4-4f13-b844-0e14e2aef915</entry>
 134             <entry>Home Partition</entry>
 135             <entry>The first home partition on the disk the root partition is located on is mounted to <filename>/home</filename>.</entry>
 136           </row>
 137           <row>
 138             <entry>3b8f8425-20e0-4f3b-907f-1a25a76f98e8</entry>
 139             <entry>Server Data Partition</entry>
 140             <entry>The first server data partition on the disk the root partition is located on is mounted to <filename>/srv</filename>.</entry>
 141           </row>
 142           <row>
 143             <entry>0657fd6d-a4ab-43c4-84e5-0933c84b4f4f</entry>
 144             <entry>Swap</entry>
 145             <entry>All swap partitions located on the disk the root partition is located on are enabled.</entry>
 146           </row>
 147           <row>
 148             <entry>c12a7328-f81f-11d2-ba4b-00a0c93ec93b</entry>
 149             <entry>EFI System Partition (ESP)</entry>
 150             <entry>The first ESP located on the disk the root partition is located on is mounted to <filename>/boot</filename> or <filename>/efi</filename>, see below.</entry>
 151           </row>
 152         </tbody>
 153       </tgroup>
 154     </table>
 155
 156     <para>The <filename>/home</filename> and <filename>/srv</filename>
 157     partitions may be encrypted in LUKS format. In this case, a device
 158     mapper device is set up under the names
 159     <filename>/dev/mapper/home</filename> and
 160     <filename>/dev/mapper/srv</filename>. Note that this might create
 161     conflicts if the same partition is listed in
 162     <filename>/etc/crypttab</filename> with a different device mapper
 163     device name.</para>
 164
 165     <para>Mount and automount units for the EFI System Partition (ESP) are generated on EFI systems. The ESP is mounted
 166     to <filename>/boot</filename>, unless a mount point directory <filename>/efi</filename> exists, in which case it is
 167     mounted there. Since this generator creates an automount unit, the mount will only be activated on-demand, when
 168     accessed. On systems where <filename>/boot</filename> (or <filename>/efi</filename> if it exists) is an explicitly
 169     configured mount (for example, listed in <citerefentry
 170     project='man-pages'><refentrytitle>fstab</refentrytitle><manvolnum>5</manvolnum></citerefentry>) or where the
 171     <filename>/boot</filename> (or <filename>/efi</filename>) mount point is non-empty, no mount units are
 172     generated.</para>
 173
 174     <para>When using this generator in conjunction with btrfs file
 175     systems, make sure to set the correct default subvolumes on them,
 176     using <command>btrfs subvolume set-default</command>.</para>
 177
 178     <para><filename>systemd-gpt-auto-generator</filename> implements
 179     <citerefentry><refentrytitle>systemd.generator</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para>
 180   </refsect1>
 181
 182   <refsect1>
 183     <title>See Also</title>
 184     <para>
 185       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 186       <citerefentry><refentrytitle>systemd.mount</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 187       <citerefentry><refentrytitle>systemd.swap</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 188       <citerefentry><refentrytitle>systemd-fstab-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 189       <citerefentry><refentrytitle>systemd-cryptsetup@.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 190       <citerefentry project='die-net'><refentrytitle>cryptsetup</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 191       <citerefentry project='man-pages'><refentrytitle>fstab</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 192       <citerefentry project='man-pages'><refentrytitle>btrfs</refentrytitle><manvolnum>8</manvolnum></citerefentry>
 193     </para>
 194   </refsect1>
 195
 196 </refentry>