man/systemd.mount.xml

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  23
  24 <refentry id="systemd.mount">
  25   <refentryinfo>
  26     <title>systemd.mount</title>
  27     <productname>systemd</productname>
  28
  29     <authorgroup>
  30       <author>
  31         <contrib>Developer</contrib>
  32         <firstname>Lennart</firstname>
  33         <surname>Poettering</surname>
  34         <email>lennart@poettering.net</email>
  35       </author>
  36     </authorgroup>
  37   </refentryinfo>
  38
  39   <refmeta>
  40     <refentrytitle>systemd.mount</refentrytitle>
  41     <manvolnum>5</manvolnum>
  42   </refmeta>
  43
  44   <refnamediv>
  45     <refname>systemd.mount</refname>
  46     <refpurpose>Mount unit configuration</refpurpose>
  47   </refnamediv>
  48
  49   <refsynopsisdiv>
  50     <para><filename><replaceable>mount</replaceable>.mount</filename></para>
  51   </refsynopsisdiv>
  52
  53   <refsect1>
  54     <title>Description</title>
  55
  56     <para>A unit configuration file whose name ends in
  57     <literal>.mount</literal> encodes information about a file system
  58     mount point controlled and supervised by systemd.</para>
  59
  60     <para>This man page lists the configuration options specific to
  61     this unit type. See
  62     <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
  63     for the common options of all unit configuration files. The common
  64     configuration items are configured in the generic [Unit] and
  65     [Install] sections. The mount specific configuration options are
  66     configured in the [Mount] section.</para>
  67
  68     <para>Additional options are listed in
  69     <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
  70     which define the execution environment the
  71     <citerefentry project='man-pages'><refentrytitle>mount</refentrytitle><manvolnum>8</manvolnum></citerefentry>
  72     binary is executed in, and in
  73     <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
  74     which define the way the processes are terminated, and in
  75     <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
  76     which configure resource control settings for the processes of the
  77     service. Note that the User= and Group= options are not
  78     particularly useful for mount units specifying a
  79     <literal>Type=</literal> option or using configuration not
  80     specified in <filename>/etc/fstab</filename>;
  81     <citerefentry project='man-pages'><refentrytitle>mount</refentrytitle><manvolnum>8</manvolnum></citerefentry>
  82     will refuse options that are not listed in
  83     <filename>/etc/fstab</filename> if it is not run as UID 0.</para>
  84
  85     <para>Mount units must be named after the mount point directories
  86     they control. Example: the mount point
  87     <filename noindex='true'>/home/lennart</filename> must be
  88     configured in a unit file <filename>home-lennart.mount</filename>.
  89     For details about the escaping logic used to convert a file system
  90     path to a unit name, see
  91     <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
  92
  93     <para>Optionally, a mount unit may be accompanied by an automount
  94     unit, to allow on-demand or parallelized mounting. See
  95     <citerefentry><refentrytitle>systemd.automount</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
  96
  97     <para>If a mount point is beneath another mount point in the file
  98     system hierarchy, a dependency between both units is created
  99     automatically.</para>
 100
 101     <para>Mount points created at runtime (independently of unit files
 102     or <filename>/etc/fstab</filename>) will be monitored by systemd
 103     and appear like any other mount unit in systemd. See
 104     <filename>/proc/self/mountinfo</filename> description in
 105     <citerefentry project='man-pages'><refentrytitle>proc</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
 106     </para>
 107
 108     <para>Some file systems have special semantics as API file systems
 109     for kernel-to-userspace and userspace-to-userpace interfaces. Some
 110     of them may not be changed via mount units, and cannot be
 111     disabled. For a longer discussion see <ulink
 112     url="http://www.freedesktop.org/wiki/Software/systemd/APIFileSystems">API
 113     File Systems</ulink>.</para>
 114   </refsect1>
 115
 116   <refsect1>
 117     <title><filename>fstab</filename></title>
 118
 119     <para>Mount units may either be configured via unit files, or via
 120     <filename>/etc/fstab</filename> (see
 121     <citerefentry project='man-pages'><refentrytitle>fstab</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 122     for details). Mounts listed in <filename>/etc/fstab</filename>
 123     will be converted into native units dynamically at boot and when
 124     the configuration of the system manager is reloaded. In general,
 125     configuring mount points through <filename>/etc/fstab</filename>
 126     is the preferred approach. See
 127     <citerefentry><refentrytitle>systemd-fstab-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>
 128     for details about the conversion.</para>
 129
 130     <para>When reading <filename>/etc/fstab</filename> a few special
 131     mount options are understood by systemd which influence how
 132     dependencies are created for mount points. systemd will create a
 133     dependency of type <option>Wants</option> or
 134     <option>Requires</option> (see option <option>nofail</option>
 135     below), from either <filename>local-fs.target</filename> or
 136     <filename>remote-fs.target</filename>, depending whether the file
 137     system is local or remote.</para>
 138
 139     <variablelist class='fstab-options'>
 140
 141       <varlistentry>
 142         <term><option>x-systemd.automount</option></term>
 143
 144         <listitem><para>An automount unit will be created for the file
 145         system. See
 146         <citerefentry><refentrytitle>systemd.automount</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 147         for details.</para></listitem>
 148       </varlistentry>
 149
 150       <varlistentry>
 151         <term><option>x-systemd.idle-timeout=</option></term>
 152
 153         <listitem><para>Configures the idleness timeout of the
 154         automount unit. See <varname>TimeoutIdleSec=</varname> in
 155         <citerefentry><refentrytitle>systemd.automount</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 156         for details.</para></listitem>
 157       </varlistentry>
 158
 159       <varlistentry>
 160         <term><option>x-systemd.device-timeout=</option></term>
 161
 162         <listitem><para>Configure how long systemd should wait for a
 163         device to show up before giving up on an entry from
 164         <filename>/etc/fstab</filename>. Specify a time in seconds or
 165         explicitly append a unit as <literal>s</literal>,
 166         <literal>min</literal>, <literal>h</literal>,
 167         <literal>ms</literal>.</para>
 168
 169         <para>Note that this option can only be used in
 170         <filename>/etc/fstab</filename>, and will be
 171         ignored when part of <varname>Options=</varname>
 172         setting in a unit file.</para>
 173         </listitem>
 174       </varlistentry>
 175
 176       <varlistentry>
 177         <term><option>noauto</option></term>
 178         <term><option>auto</option></term>
 179
 180         <listitem><para>With <option>noauto</option>, this mount will
 181         not be added as a dependency for
 182         <filename>local-fs.target</filename> or
 183         <filename>remote-fs.target</filename>. This means that it will
 184         not be mounted automatically during boot, unless it is pulled
 185         in by some other unit. Option <option>auto</option> has the
 186         opposite meaning and is the default.</para>
 187         </listitem>
 188       </varlistentry>
 189
 190       <varlistentry>
 191         <term><option>nofail</option></term>
 192
 193         <listitem><para>With <option>nofail</option> this mount will
 194         be only wanted, not required, by
 195         <filename>local-fs.target</filename> or
 196         <filename>remote-fs.target</filename>. This means that the
 197         boot will continue even if this mount point is not mounted
 198         successfully.</para>
 199         </listitem>
 200       </varlistentry>
 201
 202       <varlistentry>
 203         <term><option>x-initrd.mount</option></term>
 204
 205         <listitem><para>An additional filesystem to be mounted in the
 206         initramfs. See <filename>initrd-fs.target</filename>
 207         description in
 208         <citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry>.
 209         </para></listitem>
 210       </varlistentry>
 211     </variablelist>
 212
 213     <para>If a mount point is configured in both
 214     <filename>/etc/fstab</filename> and a unit file that is stored
 215     below <filename>/usr</filename>, the former will take precedence.
 216     If the unit file is stored below <filename>/etc</filename>, it
 217     will take precedence. This means: native unit files take
 218     precedence over traditional configuration files, but this is
 219     superseded by the rule that configuration in
 220     <filename>/etc</filename> will always take precedence over
 221     configuration in <filename>/usr</filename>.</para>
 222   </refsect1>
 223
 224   <refsect1>
 225     <title>Options</title>
 226
 227     <para>Mount files must include a [Mount] section, which carries
 228     information about the file system mount points it supervises. A
 229     number of options that may be used in this section are shared with
 230     other unit types. These options are documented in
 231     <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 232     and
 233     <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
 234     The options specific to the [Mount] section of mount units are the
 235     following:</para>
 236
 237     <variablelist class='unit-directives'>
 238
 239       <varlistentry>
 240         <term><varname>What=</varname></term>
 241         <listitem><para>Takes an absolute path of a device node, file
 242         or other resource to mount. See
 243         <citerefentry project='man-pages'><refentrytitle>mount</refentrytitle><manvolnum>8</manvolnum></citerefentry>
 244         for details. If this refers to a device node, a dependency on
 245         the respective device unit is automatically created. (See
 246         <citerefentry><refentrytitle>systemd.device</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 247         for more information.) This option is
 248         mandatory.</para></listitem>
 249       </varlistentry>
 250
 251       <varlistentry>
 252         <term><varname>Where=</varname></term>
 253         <listitem><para>Takes an absolute path of a directory of the
 254         mount point. If the mount point does not exist at the time of
 255         mounting, it is created. This string must be reflected in the
 256         unit filename. (See above.) This option is
 257         mandatory.</para></listitem>
 258       </varlistentry>
 259
 260       <varlistentry>
 261         <term><varname>Type=</varname></term>
 262         <listitem><para>Takes a string for the file system type. See
 263         <citerefentry project='man-pages'><refentrytitle>mount</refentrytitle><manvolnum>8</manvolnum></citerefentry>
 264         for details. This setting is optional.</para></listitem>
 265       </varlistentry>
 266
 267       <varlistentry>
 268         <term><varname>Options=</varname></term>
 269
 270         <listitem><para>Mount options to use when mounting. This takes
 271         a comma-separated list of options. This setting is
 272         optional.</para></listitem>
 273       </varlistentry>
 274
 275       <varlistentry>
 276         <term><varname>SloppyOptions=</varname></term>
 277
 278         <listitem><para>Takes a boolean argument. If true, parsing of
 279         the options specified in <varname>Options=</varname> is
 280         relaxed, and unknown mount options are tolerated. This
 281         corresponds with
 282         <citerefentry project='man-pages'><refentrytitle>mount</refentrytitle><manvolnum>8</manvolnum></citerefentry>'s
 283         <parameter>-s</parameter> switch. Defaults to
 284         off.</para></listitem>
 285       </varlistentry>
 286
 287       <varlistentry>
 288         <term><varname>DirectoryMode=</varname></term>
 289         <listitem><para>Directories of mount points (and any parent
 290         directories) are automatically created if needed. This option
 291         specifies the file system access mode used when creating these
 292         directories. Takes an access mode in octal notation. Defaults
 293         to 0755.</para></listitem>
 294       </varlistentry>
 295
 296       <varlistentry>
 297         <term><varname>TimeoutSec=</varname></term>
 298         <listitem><para>Configures the time to wait for the mount
 299         command to finish. If a command does not exit within the
 300         configured time, the mount will be considered failed and be
 301         shut down again. All commands still running will be terminated
 302         forcibly via <constant>SIGTERM</constant>, and after another
 303         delay of this time with <constant>SIGKILL</constant>. (See
 304         <option>KillMode=</option> in
 305         <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>.)
 306         Takes a unit-less value in seconds, or a time span value such
 307         as "5min 20s". Pass 0 to disable the timeout logic. The
 308         default value is set from the manager configuration file's
 309         <varname>DefaultTimeoutStart=</varname>
 310         variable.</para></listitem>
 311       </varlistentry>
 312     </variablelist>
 313
 314     <para>Check
 315     <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 316     and
 317     <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 318     for more settings.</para>
 319   </refsect1>
 320
 321   <refsect1>
 322       <title>See Also</title>
 323       <para>
 324         <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 325         <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 326         <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 327         <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 328         <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 329         <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 330         <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 331         <citerefentry><refentrytitle>systemd.device</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 332         <citerefentry project='man-pages'><refentrytitle>proc</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 333         <citerefentry project='man-pages'><refentrytitle>mount</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 334         <citerefentry><refentrytitle>systemd-fstab-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 335         <citerefentry><refentrytitle>systemd.directives</refentrytitle><manvolnum>7</manvolnum></citerefentry>
 336       </para>
 337   </refsect1>
 338
 339 </refentry>