man/systemd.mount.xml

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   9   Copyright 2010 Lennart Poettering
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  24
  25 <refentry id="systemd.mount">
  26         <refentryinfo>
  27                 <title>systemd.mount</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.mount</refentrytitle>
  42                 <manvolnum>5</manvolnum>
  43         </refmeta>
  44
  45         <refnamediv>
  46                 <refname>systemd.mount</refname>
  47                 <refpurpose>Mount unit configuration</refpurpose>
  48         </refnamediv>
  49
  50         <refsynopsisdiv>
  51                 <para><filename>systemd.mount</filename></para>
  52         </refsynopsisdiv>
  53
  54         <refsect1>
  55                 <title>Description</title>
  56
  57                 <para>A unit configuration file whose name ends in
  58                 <filename>.mount</filename> encodes information about
  59                 a file system mount point controlled and supervised by
  60                 systemd.</para>
  61
  62                 <para>This man page lists the configuration options
  63                 specific to this unit type. See
  64                 <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
  65                 for the common options of all unit configuration
  66                 files. The common configuration items are configured
  67                 in the generic [Unit] and [Install] sections. The
  68                 mount specific configuration options are configured
  69                 in the [Mount] section.</para>
  70
  71                 <para>Additional options are listed in
  72                 <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
  73                 which define the execution environment the
  74                 <citerefentry><refentrytitle>mount</refentrytitle><manvolnum>8</manvolnum></citerefentry>
  75                 binary is executed in, and in
  76                 <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>
  77                 which define the way the processes are
  78                 terminated. Note that the User= and Group= options are
  79                 not particularly useful for mount units specifying a
  80                 <literal>Type=</literal> option or using configuration
  81                 not specified in <filename>/etc/fstab</filename>;
  82                 <citerefentry><refentrytitle>mount</refentrytitle><manvolnum>8</manvolnum></citerefentry>
  83                 will refuse options that aren't listed in
  84                 <filename>/etc/fstab</filename> if it is not run as
  85                 UID 0.</para>
  86
  87                 <para>Mount units must be named after the mount point
  88                 directories they control. Example: the mount point
  89                 <filename>/home/lennart</filename> must be configured
  90                 in a unit file
  91                 <filename>home-lennart.mount</filename>. For details
  92                 about the escaping logic used to convert a file system
  93                 path to a unit name see
  94                 <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
  95
  96                 <para>Optionally, a mount unit may be accompanied by
  97                 an automount unit, to allow on-demand or parallelized
  98                 mounting. See
  99                 <citerefentry><refentrytitle>systemd.automount</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
 100
 101                 <para>If a mount point is beneath another mount point
 102                 in the file system hierarchy, a dependency between both
 103                 units is created automatically.</para>
 104
 105                 <para>Mount points created at runtime (independently of
 106                 unit files or <filename>/etc/fstab</filename>) will be
 107                 monitored by systemd and appear like any other mount
 108                 unit in systemd.</para>
 109
 110                 <para>Some file systems have special semantics as API
 111                 file systems for kernel-to-userspace and
 112                 userspace-to-userpace interfaces. Some of them may not
 113                 be changed via mount units, and cannot be disabled.
 114                 For a longer discussion see <ulink
 115                 url="http://www.freedesktop.org/wiki/Software/systemd/APIFileSystems">API
 116                 File Systems</ulink>.</para>
 117         </refsect1>
 118
 119         <refsect1>
 120                 <title><filename>/etc/fstab</filename></title>
 121
 122                 <para>Mount units may either be configured via unit
 123                 files, or via <filename>/etc/fstab</filename> (see
 124                 <citerefentry><refentrytitle>fstab</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 125                 for details). Mounts listed in
 126                 <filename>/etc/fstab</filename> will be converted into
 127                 native units dynamically at boot and when the
 128                 configuration of the system manager is reloaded. See
 129                 <citerefentry><refentrytitle>systemd-fstab-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>
 130                 for details about the conversion.</para>
 131
 132                 <para>When reading <filename>/etc/fstab</filename> a
 133                 few special mount options are understood by systemd
 134                 which influence how dependencies are created for mount
 135                 points from <filename>/etc/fstab</filename>. systemd
 136                 will create a dependency of type
 137                 <option>Wants</option> from either
 138                 <filename>local-fs.target</filename> or
 139                 <filename>remote-fs.target</filename>, depending
 140                 whether the file system is local or remote. If
 141                 <option>x-systemd.automount</option> is set, an
 142                 automount unit will be created for the file
 143                 system. See
 144                 <citerefentry><refentrytitle>systemd.automount</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 145                 for details. If
 146                 <option>x-systemd.device-timeout=</option> is
 147                 specified it may be used to configure how long systemd
 148                 should wait for a device to show up before giving up
 149                 on an entry from
 150                 <filename>/etc/fstab</filename>. Specify a time in
 151                 seconds or explicitly specify a unit as
 152                 <literal>s</literal>, <literal>min</literal>,
 153                 <literal>h</literal>, <literal>ms</literal>.</para>
 154
 155                 <para>If a mount point is configured in both
 156                 <filename>/etc/fstab</filename> and a unit file, the
 157                 configuration in the latter takes precedence.</para>
 158         </refsect1>
 159
 160         <refsect1>
 161                 <title>Options</title>
 162
 163                 <para>Mount files must include a [Mount] section,
 164                 which carries information about the file system mount points it
 165                 supervises. A number of options that may be used in
 166                 this section are shared with other unit types. These
 167                 options are documented in
 168                 <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 169                 and
 170                 <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>. The
 171                 options specific to the [Mount] section of mount
 172                 units are the following:</para>
 173
 174                 <variablelist>
 175
 176                         <varlistentry>
 177                                 <term><varname>What=</varname></term>
 178                                 <listitem><para>Takes an absolute path
 179                                 of a device node, file or other
 180                                 resource to mount. See
 181                                 <citerefentry><refentrytitle>mount</refentrytitle><manvolnum>8</manvolnum></citerefentry>
 182                                 for details. If this refers to a
 183                                 device node, a dependency on the
 184                                 respective device unit is
 185                                 automatically created. (See
 186                                 <citerefentry><refentrytitle>systemd.device</refentrytitle><manvolnum>5</manvolnum></citerefentry> for more information.)
 187                                 This option is
 188                                 mandatory.</para></listitem>
 189                         </varlistentry>
 190
 191                         <varlistentry>
 192                                 <term><varname>Where=</varname></term>
 193                                 <listitem><para>Takes an absolute path
 194                                 of a directory of the mount point. If
 195                                 the mount point does not exist at the
 196                                 time of mounting, it is created. This
 197                                 string must be reflected in the unit
 198                                 file name. (See above.) This option is
 199                                 mandatory.</para></listitem>
 200                         </varlistentry>
 201
 202                         <varlistentry>
 203                                 <term><varname>Type=</varname></term>
 204                                 <listitem><para>Takes a string for the
 205                                 filesystem type. See
 206                                 <citerefentry><refentrytitle>mount</refentrytitle><manvolnum>8</manvolnum></citerefentry>
 207                                 for details. This setting is
 208                                 optional.</para></listitem>
 209                         </varlistentry>
 210
 211                         <varlistentry>
 212                                 <term><varname>Options=</varname></term>
 213
 214                                 <listitem><para>Mount options to use
 215                                 when mounting. This takes a comma
 216                                 separated list of options. This
 217                                 setting is optional.</para></listitem>
 218                         </varlistentry>
 219
 220                         <varlistentry>
 221                                 <term><varname>DirectoryMode=</varname></term>
 222                                 <listitem><para>Directories of mount
 223                                 points (and any parent directories)
 224                                 are automatically created if
 225                                 needed. This option specifies the file
 226                                 system access mode used when creating
 227                                 these directories. Takes an access
 228                                 mode in octal notation. Defaults to
 229                                 0755.</para></listitem>
 230                         </varlistentry>
 231
 232                         <varlistentry>
 233                                 <term><varname>TimeoutSec=</varname></term>
 234                                 <listitem><para>Configures the time to
 235                                 wait for the mount command to
 236                                 finish. If a command does not exit
 237                                 within the configured time the mount
 238                                 will be considered failed and be shut
 239                                 down again. All commands still running
 240                                 will be terminated forcibly via
 241                                 SIGTERM, and after another delay of
 242                                 this time with SIGKILL. (See
 243                                 <option>KillMode=</option> in
 244                                 <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>.)
 245                                 Takes a unit-less value in seconds, or
 246                                 a time span value such as "5min
 247                                 20s". Pass 0 to disable the timeout
 248                                 logic. Defaults to
 249                                 90s.</para></listitem>
 250                         </varlistentry>
 251                 </variablelist>
 252
 253                 <para>Check
 254                 <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 255                 and
 256                 <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 257                 for more settings.</para>
 258         </refsect1>
 259
 260         <refsect1>
 261                 <title>Compatibility Options</title>
 262
 263                 <para>The following option is also available in the
 264                 <literal>[Mount]</literal> section, but exists purely
 265                 for compatibility reasons and should not be used in
 266                 newly written mount files.</para>
 267
 268                 <variablelist>
 269                         <varlistentry>
 270                                 <term><varname>FsckPassNo=</varname></term>
 271
 272                                 <listitem><para>The pass number for
 273                                 the file system checking service for
 274                                 this mount. See
 275                                 <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 276                                 for more information on this setting.
 277                                 </para></listitem>
 278                         </varlistentry>
 279                 </variablelist>
 280         </refsect1>
 281
 282         <refsect1>
 283                   <title>See Also</title>
 284                   <para>
 285                           <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 286                           <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 287                           <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 288                           <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 289                           <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 290                           <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 291                           <citerefentry><refentrytitle>systemd.device</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 292                           <citerefentry><refentrytitle>mount</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 293                           <citerefentry><refentrytitle>systemd-fstab-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>
 294                   </para>
 295         </refsect1>
 296
 297 </refentry>