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