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>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. systemd will create a dependency of type
 146                 <option>Wants</option> or <option>Requires</option>
 147                 (see option <option>nofail</option> below), from
 148                 either <filename>local-fs.target</filename> or
 149                 <filename>remote-fs.target</filename>, depending
 150                 whether the file system is local or remote.</para>
 151
 152                 <variablelist class='fstab-options'>
 153
 154                   <varlistentry>
 155                     <term><option>x-systemd.automount</option></term>
 156
 157                     <listitem><para>An automount unit will be created
 158                     for the file system. See
 159                     <citerefentry><refentrytitle>systemd.automount</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 160                     for details.</para></listitem>
 161                   </varlistentry>
 162
 163                   <varlistentry>
 164                     <term><option>x-systemd.device-timeout=</option></term>
 165
 166                     <listitem><para>Configure how long systemd should
 167                     wait for a device to show up before giving up on
 168                     an entry from
 169                     <filename>/etc/fstab</filename>. Specify a time in
 170                     seconds or explicitly append a unit as
 171                     <literal>s</literal>, <literal>min</literal>,
 172                     <literal>h</literal>,
 173                     <literal>ms</literal>.</para>
 174
 175                     <para>Note that this option can only be used in
 176                     <filename>/etc/fstab</filename>, and will be
 177                     ignored when part of <varname>Options=</varname>
 178                     setting in a unit file.</para>
 179                     </listitem>
 180                   </varlistentry>
 181
 182                   <varlistentry>
 183                     <term><option>noauto</option></term>
 184                     <term><option>auto</option></term>
 185
 186                     <listitem><para>With <option>noauto</option>, this
 187                     mount will not be added as a dependency for
 188                     <filename>local-fs.target</filename> or
 189                     <filename>remote-fs.target</filename>. This means
 190                     that it will not be mounted automatically during
 191                     boot, unless it is pulled in by some other
 192                     unit. Option <option>auto</option> has the
 193                     opposite meaning and is the default.</para>
 194                     </listitem>
 195                   </varlistentry>
 196
 197                   <varlistentry>
 198                     <term><option>nofail</option></term>
 199
 200                     <listitem><para>With <option>nofail</option> this
 201                     mount will be only wanted, not required, by
 202                     <filename>local-fs.target</filename> or
 203                     <filename>remote-fs.target</filename>. This means
 204                     that the boot will continue even if this mount
 205                     point is not mounted successfully.</para>
 206                     </listitem>
 207                   </varlistentry>
 208
 209                   <varlistentry>
 210                     <term><option>x-initrd.mount</option></term>
 211
 212                     <listitem><para>An additional filesystem to be
 213                     mounted in the initramfs. See
 214                     <filename>initrd-fs.target</filename> description
 215                     in
 216                     <citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry>.
 217                     </para></listitem>
 218                   </varlistentry>
 219                 </variablelist>
 220
 221                 <para>If a mount point is configured in both
 222                 <filename>/etc/fstab</filename> and a unit file that
 223                 is stored below <filename>/usr</filename>, the former
 224                 will take precedence. If the unit file is stored below
 225                 <filename>/etc</filename>, it will take
 226                 precedence. This means: native unit files take
 227                 precedence over traditional configuration files, but
 228                 this is superseded by the rule that configuration in
 229                 <filename>/etc</filename> will always take precedence
 230                 over configuration in
 231                 <filename>/usr</filename>.</para>
 232         </refsect1>
 233
 234         <refsect1>
 235                 <title>Options</title>
 236
 237                 <para>Mount files must include a [Mount] section,
 238                 which carries information about the file system mount points it
 239                 supervises. A number of options that may be used in
 240                 this section are shared with other unit types. These
 241                 options are documented in
 242                 <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 243                 and
 244                 <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>. The
 245                 options specific to the [Mount] section of mount
 246                 units are the following:</para>
 247
 248                 <variablelist class='unit-directives'>
 249
 250                         <varlistentry>
 251                                 <term><varname>What=</varname></term>
 252                                 <listitem><para>Takes an absolute path
 253                                 of a device node, file or other
 254                                 resource to mount. See
 255                                 <citerefentry><refentrytitle>mount</refentrytitle><manvolnum>8</manvolnum></citerefentry>
 256                                 for details. If this refers to a
 257                                 device node, a dependency on the
 258                                 respective device unit is
 259                                 automatically created. (See
 260                                 <citerefentry><refentrytitle>systemd.device</refentrytitle><manvolnum>5</manvolnum></citerefentry> for more information.)
 261                                 This option is
 262                                 mandatory.</para></listitem>
 263                         </varlistentry>
 264
 265                         <varlistentry>
 266                                 <term><varname>Where=</varname></term>
 267                                 <listitem><para>Takes an absolute path
 268                                 of a directory of the mount point. If
 269                                 the mount point does not exist at the
 270                                 time of mounting, it is created. This
 271                                 string must be reflected in the unit
 272                                 filename. (See above.) This option is
 273                                 mandatory.</para></listitem>
 274                         </varlistentry>
 275
 276                         <varlistentry>
 277                                 <term><varname>Type=</varname></term>
 278                                 <listitem><para>Takes a string for the
 279                                 file system type. See
 280                                 <citerefentry><refentrytitle>mount</refentrytitle><manvolnum>8</manvolnum></citerefentry>
 281                                 for details. This setting is
 282                                 optional.</para></listitem>
 283                         </varlistentry>
 284
 285                         <varlistentry>
 286                                 <term><varname>Options=</varname></term>
 287
 288                                 <listitem><para>Mount options to use
 289                                 when mounting. This takes a
 290                                 comma-separated list of options. This
 291                                 setting is optional.</para></listitem>
 292                         </varlistentry>
 293
 294                         <varlistentry>
 295                                 <term><varname>SloppyOptions=</varname></term>
 296
 297                                 <listitem><para>Takes a boolean
 298                                 argument. If true, parsing of the
 299                                 options specified in
 300                                 <varname>Options=</varname> is
 301                                 relaxed, and unknown mount options are
 302                                 tolerated. This corresponds with
 303                                 <citerefentry><refentrytitle>mount</refentrytitle><manvolnum>8</manvolnum></citerefentry>'s
 304                                 <parameter>-s</parameter>
 305                                 switch. Defaults to
 306                                 off.</para></listitem>
 307                         </varlistentry>
 308
 309                         <varlistentry>
 310                                 <term><varname>DirectoryMode=</varname></term>
 311                                 <listitem><para>Directories of mount
 312                                 points (and any parent directories)
 313                                 are automatically created if
 314                                 needed. This option specifies the file
 315                                 system access mode used when creating
 316                                 these directories. Takes an access
 317                                 mode in octal notation. Defaults to
 318                                 0755.</para></listitem>
 319                         </varlistentry>
 320
 321                         <varlistentry>
 322                                 <term><varname>TimeoutSec=</varname></term>
 323                                 <listitem><para>Configures the time to
 324                                 wait for the mount command to
 325                                 finish. If a command does not exit
 326                                 within the configured time, the mount
 327                                 will be considered failed and be shut
 328                                 down again. All commands still running
 329                                 will be terminated forcibly via
 330                                 <constant>SIGTERM</constant>, and after another delay of
 331                                 this time with <constant>SIGKILL</constant>. (See
 332                                 <option>KillMode=</option> in
 333                                 <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>.)
 334                                 Takes a unit-less value in seconds, or
 335                                 a time span value such as "5min
 336                                 20s". Pass 0 to disable the timeout
 337                                 logic. The default value is set from the manager configuration
 338                                 file's <varname>DefaultTimeoutStart=</varname> variable.</para></listitem>
 339                         </varlistentry>
 340                 </variablelist>
 341
 342                 <para>Check
 343                 <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 344                 and
 345                 <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 346                 for more settings.</para>
 347         </refsect1>
 348
 349         <refsect1>
 350                   <title>See Also</title>
 351                   <para>
 352                           <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 353                           <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 354                           <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 355                           <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 356                           <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 357                           <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 358                           <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 359                           <citerefentry><refentrytitle>systemd.device</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 360                           <citerefentry project='man-pages'><refentrytitle>proc</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 361                           <citerefentry><refentrytitle>mount</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 362                           <citerefentry><refentrytitle>systemd-fstab-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 363                           <citerefentry><refentrytitle>systemd.directives</refentrytitle><manvolnum>7</manvolnum></citerefentry>
 364                   </para>
 365         </refsect1>
 366
 367 </refentry>