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><replaceable>mount</replaceable>.mount</filename></para>
  52         </refsynopsisdiv>
  53
  54         <refsect1>
  55                 <title>Description</title>
  56
  57                 <para>A unit configuration file whose name ends in
  58                 <literal>.mount</literal> 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 terminated, and
  78                 in
  79                 <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
  80                 which configure resource control settings for the
  81                 processes of the service. Note that the User= and
  82                 Group= options are not particularly useful for mount
  83                 units specifying a <literal>Type=</literal> option or
  84                 using configuration not specified in
  85                 <filename>/etc/fstab</filename>;
  86                 <citerefentry><refentrytitle>mount</refentrytitle><manvolnum>8</manvolnum></citerefentry>
  87                 will refuse options that are not listed in
  88                 <filename>/etc/fstab</filename> if it is not run as
  89                 UID 0.</para>
  90
  91                 <para>Mount units must be named after the mount point
  92                 directories they control. Example: the mount point
  93                 <filename noindex='true'>/home/lennart</filename> must be configured
  94                 in a unit file
  95                 <filename>home-lennart.mount</filename>. For details
  96                 about the escaping logic used to convert a file system
  97                 path to a unit name, see
  98                 <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
  99
 100                 <para>Optionally, a mount unit may be accompanied by
 101                 an automount unit, to allow on-demand or parallelized
 102                 mounting. See
 103                 <citerefentry><refentrytitle>systemd.automount</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
 104
 105                 <para>If a mount point is beneath another mount point
 106                 in the file system hierarchy, a dependency between both
 107                 units is created automatically.</para>
 108
 109                 <para>Mount points created at runtime (independently of
 110                 unit files or <filename>/etc/fstab</filename>) will be
 111                 monitored by systemd and appear like any other mount
 112                 unit in systemd.
 113                 See <filename>/proc/self/mountinfo</filename> description
 114                 in <citerefentry project='man-pages'><refentrytitle>proc</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
 115                 </para>
 116
 117                 <para>Some file systems have special semantics as API
 118                 file systems for kernel-to-userspace and
 119                 userspace-to-userpace interfaces. Some of them may not
 120                 be changed via mount units, and cannot be disabled.
 121                 For a longer discussion see <ulink
 122                 url="http://www.freedesktop.org/wiki/Software/systemd/APIFileSystems">API
 123                 File Systems</ulink>.</para>
 124         </refsect1>
 125
 126         <refsect1>
 127                 <title><filename>/etc/fstab</filename></title>
 128
 129                 <para>Mount units may either be configured via unit
 130                 files, or via <filename>/etc/fstab</filename> (see
 131                 <citerefentry><refentrytitle>fstab</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 132                 for details). Mounts listed in
 133                 <filename>/etc/fstab</filename> will be converted into
 134                 native units dynamically at boot and when the
 135                 configuration of the system manager is reloaded. In
 136                 general, configuring mount points through
 137                 <filename>/etc/fstab</filename> is the preferred
 138                 approach. See
 139                 <citerefentry><refentrytitle>systemd-fstab-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>
 140                 for details about the conversion.</para>
 141
 142                 <para>When reading <filename>/etc/fstab</filename> a
 143                 few special mount options are understood by systemd
 144                 which influence how dependencies are created for mount
 145                 points from <filename>/etc/fstab</filename>. systemd
 146                 will create a dependency of type
 147                 <option>Wants</option> or <option>Requires</option>
 148                 (see option <option>nofail</option> below), from
 149                 either <filename>local-fs.target</filename> or
 150                 <filename>remote-fs.target</filename>, depending
 151                 whether the file system is local or remote.</para>
 152
 153                 <variablelist class='fstab-options'>
 154
 155                   <varlistentry>
 156                     <term><option>x-systemd.automount</option></term>
 157
 158                     <listitem><para>An automount unit will be created
 159                     for the file system. See
 160                     <citerefentry><refentrytitle>systemd.automount</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 161                     for details.</para></listitem>
 162                   </varlistentry>
 163
 164                   <varlistentry>
 165                     <term><option>x-systemd.device-timeout=</option></term>
 166
 167                     <listitem><para>Configure how long systemd should
 168                     wait for a device to show up before giving up on
 169                     an entry from
 170                     <filename>/etc/fstab</filename>. Specify a time in
 171                     seconds or explicitly append a unit as
 172                     <literal>s</literal>, <literal>min</literal>,
 173                     <literal>h</literal>,
 174                     <literal>ms</literal>.</para>
 175
 176                     <para>Note that this option can only be used in
 177                     <filename>/etc/fstab</filename>, and will be
 178                     ignored when part of <varname>Options=</varname>
 179                     setting in a unit file.</para>
 180                     </listitem>
 181                   </varlistentry>
 182
 183                   <varlistentry>
 184                     <term><option>nofail</option></term>
 185                     <term><option>fail</option></term>
 186
 187                     <listitem><para>With <option>nofail</option> this
 188                     mount will be only wanted, not required, by the
 189                     <filename>local-fs.target</filename>. This means
 190                     that the boot will continue even if this mount
 191                     point is not mounted successfully. Option
 192                     <option>fail</option> has the opposite meaning and
 193                     is the default.</para>
 194                     </listitem>
 195                   </varlistentry>
 196
 197                   <varlistentry>
 198                     <term><option>noauto</option></term>
 199                     <term><option>auto</option></term>
 200
 201                     <listitem><para>With <option>noauto</option>, this
 202                     mount will not be added as a dependency for
 203                     <filename>local-fs.target</filename>. This means
 204                     that it will not be mounted automatically during
 205                     boot, unless it is pulled in by some other
 206                     unit. Option <option>auto</option> has the
 207                     opposite meaning and is the default.</para>
 208                     </listitem>
 209                   </varlistentry>
 210
 211                   <varlistentry>
 212                     <term><option>x-initrd.mount</option></term>
 213
 214                     <listitem><para>An additional filesystem to be
 215                     mounted in the initramfs. See
 216                     <filename>initrd-fs.target</filename> description
 217                     in
 218                     <citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry>.
 219                     </para></listitem>
 220                   </varlistentry>
 221                 </variablelist>
 222
 223                 <para>If a mount point is configured in both
 224                 <filename>/etc/fstab</filename> and a unit file that
 225                 is stored below <filename>/usr</filename>, the former
 226                 will take precedence. If the unit file is stored below
 227                 <filename>/etc</filename>, it will take
 228                 precedence. This means: native unit files take
 229                 precedence over traditional configuration files, but
 230                 this is superseded by the rule that configuration in
 231                 <filename>/etc</filename> will always take precedence
 232                 over configuration in
 233                 <filename>/usr</filename>.</para>
 234         </refsect1>
 235
 236         <refsect1>
 237                 <title>Options</title>
 238
 239                 <para>Mount files must include a [Mount] section,
 240                 which carries information about the file system mount points it
 241                 supervises. A number of options that may be used in
 242                 this section are shared with other unit types. These
 243                 options are documented in
 244                 <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 245                 and
 246                 <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>. The
 247                 options specific to the [Mount] section of mount
 248                 units are the following:</para>
 249
 250                 <variablelist class='unit-directives'>
 251
 252                         <varlistentry>
 253                                 <term><varname>What=</varname></term>
 254                                 <listitem><para>Takes an absolute path
 255                                 of a device node, file or other
 256                                 resource to mount. See
 257                                 <citerefentry><refentrytitle>mount</refentrytitle><manvolnum>8</manvolnum></citerefentry>
 258                                 for details. If this refers to a
 259                                 device node, a dependency on the
 260                                 respective device unit is
 261                                 automatically created. (See
 262                                 <citerefentry><refentrytitle>systemd.device</refentrytitle><manvolnum>5</manvolnum></citerefentry> for more information.)
 263                                 This option is
 264                                 mandatory.</para></listitem>
 265                         </varlistentry>
 266
 267                         <varlistentry>
 268                                 <term><varname>Where=</varname></term>
 269                                 <listitem><para>Takes an absolute path
 270                                 of a directory of the mount point. If
 271                                 the mount point does not exist at the
 272                                 time of mounting, it is created. This
 273                                 string must be reflected in the unit
 274                                 filename. (See above.) This option is
 275                                 mandatory.</para></listitem>
 276                         </varlistentry>
 277
 278                         <varlistentry>
 279                                 <term><varname>Type=</varname></term>
 280                                 <listitem><para>Takes a string for the
 281                                 file system type. See
 282                                 <citerefentry><refentrytitle>mount</refentrytitle><manvolnum>8</manvolnum></citerefentry>
 283                                 for details. This setting is
 284                                 optional.</para></listitem>
 285                         </varlistentry>
 286
 287                         <varlistentry>
 288                                 <term><varname>Options=</varname></term>
 289
 290                                 <listitem><para>Mount options to use
 291                                 when mounting. This takes a
 292                                 comma-separated list of options. This
 293                                 setting is optional.</para></listitem>
 294                         </varlistentry>
 295
 296                         <varlistentry>
 297                                 <term><varname>SloppyOptions=</varname></term>
 298
 299                                 <listitem><para>Takes a boolean
 300                                 argument. If true, parsing of the
 301                                 options specified in
 302                                 <varname>Options=</varname> is
 303                                 relaxed, and unknown mount options are
 304                                 tolerated. This corresponds with
 305                                 <citerefentry><refentrytitle>mount</refentrytitle><manvolnum>8</manvolnum></citerefentry>'s
 306                                 <parameter>-s</parameter>
 307                                 switch. Defaults to
 308                                 off.</para></listitem>
 309                         </varlistentry>
 310
 311                         <varlistentry>
 312                                 <term><varname>DirectoryMode=</varname></term>
 313                                 <listitem><para>Directories of mount
 314                                 points (and any parent directories)
 315                                 are automatically created if
 316                                 needed. This option specifies the file
 317                                 system access mode used when creating
 318                                 these directories. Takes an access
 319                                 mode in octal notation. Defaults to
 320                                 0755.</para></listitem>
 321                         </varlistentry>
 322
 323                         <varlistentry>
 324                                 <term><varname>TimeoutSec=</varname></term>
 325                                 <listitem><para>Configures the time to
 326                                 wait for the mount command to
 327                                 finish. If a command does not exit
 328                                 within the configured time, the mount
 329                                 will be considered failed and be shut
 330                                 down again. All commands still running
 331                                 will be terminated forcibly via
 332                                 <constant>SIGTERM</constant>, and after another delay of
 333                                 this time with <constant>SIGKILL</constant>. (See
 334                                 <option>KillMode=</option> in
 335                                 <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>.)
 336                                 Takes a unit-less value in seconds, or
 337                                 a time span value such as "5min
 338                                 20s". Pass 0 to disable the timeout
 339                                 logic. The default value is set from the manager configuration
 340                                 file's <varname>DefaultTimeoutStart=</varname> variable.</para></listitem>
 341                         </varlistentry>
 342                 </variablelist>
 343
 344                 <para>Check
 345                 <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 346                 and
 347                 <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 348                 for more settings.</para>
 349         </refsect1>
 350
 351         <refsect1>
 352                   <title>See Also</title>
 353                   <para>
 354                           <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 355                           <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 356                           <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 357                           <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 358                           <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 359                           <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 360                           <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 361                           <citerefentry><refentrytitle>systemd.device</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 362                           <citerefentry project='man-pages'><refentrytitle>proc</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 363                           <citerefentry><refentrytitle>mount</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 364                           <citerefentry><refentrytitle>systemd-fstab-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 365                           <citerefentry><refentrytitle>systemd.directives</refentrytitle><manvolnum>7</manvolnum></citerefentry>
 366                   </para>
 367         </refsect1>
 368
 369 </refentry>