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