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>systemd.mount</filename></para>
  52         </refsynopsisdiv>
  53
  54         <refsect1>
  55                 <title>Description</title>
  56
  57                 <para>A unit configuration file whose name ends in
  58                 <filename>.mount</filename> 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
  78                 terminated. Note that the User= and Group= options are
  79                 not particularly useful for mount units specifying a
  80                 <literal>Type=</literal> option or using configuration
  81                 not specified in <filename>/etc/fstab</filename>;
  82                 <citerefentry><refentrytitle>mount</refentrytitle><manvolnum>8</manvolnum></citerefentry>
  83                 will refuse options that aren't listed in
  84                 <filename>/etc/fstab</filename> if it is not run as
  85                 UID 0.</para>
  86
  87                 <para>Mount units must be named after the mount point
  88                 directories they control. Example: the mount point
  89                 <filename>/home/lennart</filename> must be configured
  90                 in a unit file
  91                 <filename>home-lennart.mount</filename>. For details
  92                 about the escaping logic used to convert a file system
  93                 path to a unit name see
  94                 <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
  95
  96                 <para>Optionally, a mount unit may be accompanied by
  97                 an automount unit, to allow on-demand or parallelized
  98                 mounting. See
  99                 <citerefentry><refentrytitle>systemd.automount</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
 100
 101                 <para>If a mount point is beneath another mount point
 102                 in the file system hierarchy, a dependency between both
 103                 units is created automatically.</para>
 104
 105                 <para>Mount points created at runtime (independently of
 106                 unit files or <filename>/etc/fstab</filename>) will be
 107                 monitored by systemd and appear like any other mount
 108                 unit in systemd.</para>
 109
 110                 <para>Some file systems have special semantics as API
 111                 file systems for kernel-to-userspace and
 112                 userspace-to-userpace interfaces. Some of them may not
 113                 be changed via mount units, and cannot be disabled.
 114                 For a longer discussion see <ulink
 115                 url="http://www.freedesktop.org/wiki/Software/systemd/APIFileSystems">API
 116                 File Systems</ulink>.</para>
 117         </refsect1>
 118
 119         <refsect1>
 120                 <title><filename>/etc/fstab</filename></title>
 121
 122                 <para>Mount units may either be configured via unit
 123                 files, or via <filename>/etc/fstab</filename> (see
 124                 <citerefentry><refentrytitle>fstab</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 125                 for details). Mounts listed in
 126                 <filename>/etc/fstab</filename> will be converted into
 127                 native units dynamically at boot and when the
 128                 configuration of the system manager is reloaded. See
 129                 <citerefentry><refentrytitle>systemd-fstab-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>
 130                 for details about the conversion.</para>
 131
 132                 <para>When reading <filename>/etc/fstab</filename> a
 133                 few special mount options are understood by systemd
 134                 which influence how dependencies are created for mount
 135                 points from <filename>/etc/fstab</filename>. systemd
 136                 will create a dependency of type
 137                 <option>Wants</option> from either
 138                 <filename>local-fs.target</filename> or
 139                 <filename>remote-fs.target</filename>, depending
 140                 whether the file system is local or remote. If
 141                 <option>x-systemd.automount</option> is set, an
 142                 automount unit will be created for the file
 143                 system. See
 144                 <citerefentry><refentrytitle>systemd.automount</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 145                 for details. If
 146                 <option>x-systemd.device-timeout=</option> is
 147                 specified it may be used to configure how long systemd
 148                 should wait for a device to show up before giving up
 149                 on an entry from
 150                 <filename>/etc/fstab</filename>. Specify a time in
 151                 seconds or explicitly specify a unit as
 152                 <literal>s</literal>, <literal>min</literal>,
 153                 <literal>h</literal>, <literal>ms</literal>.</para>
 154
 155                 <para>If a mount point is configured in both
 156                 <filename>/etc/fstab</filename> and a unit file that
 157                 is stored below <filename>/usr</filename> the former
 158                 will take precedence. If the unit file is stored below
 159                 <filename>/etc</filename> it will take
 160                 precedence. This means: native unit files take
 161                 precedence over traditional configuration files, but
 162                 this is superseded by the rule that configuration in
 163                 <filename>/etc</filename> will always take precedence
 164                 over configuration in
 165                 <filename>/usr</filename>.</para>
 166         </refsect1>
 167
 168         <refsect1>
 169                 <title>Options</title>
 170
 171                 <para>Mount files must include a [Mount] section,
 172                 which carries information about the file system mount points it
 173                 supervises. A number of options that may be used in
 174                 this section are shared with other unit types. These
 175                 options are documented in
 176                 <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 177                 and
 178                 <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>. The
 179                 options specific to the [Mount] section of mount
 180                 units are the following:</para>
 181
 182                 <variablelist>
 183
 184                         <varlistentry>
 185                                 <term><varname>What=</varname></term>
 186                                 <listitem><para>Takes an absolute path
 187                                 of a device node, file or other
 188                                 resource to mount. See
 189                                 <citerefentry><refentrytitle>mount</refentrytitle><manvolnum>8</manvolnum></citerefentry>
 190                                 for details. If this refers to a
 191                                 device node, a dependency on the
 192                                 respective device unit is
 193                                 automatically created. (See
 194                                 <citerefentry><refentrytitle>systemd.device</refentrytitle><manvolnum>5</manvolnum></citerefentry> for more information.)
 195                                 This option is
 196                                 mandatory.</para></listitem>
 197                         </varlistentry>
 198
 199                         <varlistentry>
 200                                 <term><varname>Where=</varname></term>
 201                                 <listitem><para>Takes an absolute path
 202                                 of a directory of the mount point. If
 203                                 the mount point does not exist at the
 204                                 time of mounting, it is created. This
 205                                 string must be reflected in the unit
 206                                 file name. (See above.) This option is
 207                                 mandatory.</para></listitem>
 208                         </varlistentry>
 209
 210                         <varlistentry>
 211                                 <term><varname>Type=</varname></term>
 212                                 <listitem><para>Takes a string for the
 213                                 filesystem type. See
 214                                 <citerefentry><refentrytitle>mount</refentrytitle><manvolnum>8</manvolnum></citerefentry>
 215                                 for details. This setting is
 216                                 optional.</para></listitem>
 217                         </varlistentry>
 218
 219                         <varlistentry>
 220                                 <term><varname>Options=</varname></term>
 221
 222                                 <listitem><para>Mount options to use
 223                                 when mounting. This takes a comma
 224                                 separated list of options. This
 225                                 setting is optional.</para></listitem>
 226                         </varlistentry>
 227
 228                         <varlistentry>
 229                                 <term><varname>DirectoryMode=</varname></term>
 230                                 <listitem><para>Directories of mount
 231                                 points (and any parent directories)
 232                                 are automatically created if
 233                                 needed. This option specifies the file
 234                                 system access mode used when creating
 235                                 these directories. Takes an access
 236                                 mode in octal notation. Defaults to
 237                                 0755.</para></listitem>
 238                         </varlistentry>
 239
 240                         <varlistentry>
 241                                 <term><varname>TimeoutSec=</varname></term>
 242                                 <listitem><para>Configures the time to
 243                                 wait for the mount command to
 244                                 finish. If a command does not exit
 245                                 within the configured time the mount
 246                                 will be considered failed and be shut
 247                                 down again. All commands still running
 248                                 will be terminated forcibly via
 249                                 SIGTERM, and after another delay of
 250                                 this time with SIGKILL. (See
 251                                 <option>KillMode=</option> in
 252                                 <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>.)
 253                                 Takes a unit-less value in seconds, or
 254                                 a time span value such as "5min
 255                                 20s". Pass 0 to disable the timeout
 256                                 logic. Defaults to
 257                                 90s.</para></listitem>
 258                         </varlistentry>
 259                 </variablelist>
 260
 261                 <para>Check
 262                 <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 263                 and
 264                 <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 265                 for more settings.</para>
 266         </refsect1>
 267
 268         <refsect1>
 269                 <title>Compatibility Options</title>
 270
 271                 <para>The following option is also available in the
 272                 <literal>[Mount]</literal> section, but exists purely
 273                 for compatibility reasons and should not be used in
 274                 newly written mount files.</para>
 275
 276                 <variablelist>
 277                         <varlistentry>
 278                                 <term><varname>FsckPassNo=</varname></term>
 279
 280                                 <listitem><para>The pass number for
 281                                 the file system checking service for
 282                                 this mount. See
 283                                 <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 284                                 for more information on this setting.
 285                                 </para></listitem>
 286                         </varlistentry>
 287                 </variablelist>
 288         </refsect1>
 289
 290         <refsect1>
 291                   <title>See Also</title>
 292                   <para>
 293                           <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 294                           <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 295                           <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 296                           <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 297                           <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 298                           <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 299                           <citerefentry><refentrytitle>systemd.device</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 300                           <citerefentry><refentrytitle>mount</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 301                           <citerefentry><refentrytitle>systemd-fstab-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 302                           <citerefentry><refentrytitle>systemd.directives</refentrytitle><manvolnum>7</manvolnum></citerefentry>
 303                   </para>
 304         </refsect1>
 305
 306 </refentry>