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diff --git a/man/systemd.swap.xml b/man/systemd.swap.xml new file mode 100644 index 0000000..1c019b2 --- /dev/null +++ b/man/systemd.swap.xml @@ -0,0 +1,269 @@ +<?xml version='1.0'?> <!--*-nxml-*--> +<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN" + "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"> +<!-- SPDX-License-Identifier: LGPL-2.1-or-later --> + +<refentry id="systemd.swap" xmlns:xi="http://www.w3.org/2001/XInclude"> + <refentryinfo> + <title>systemd.swap</title> + <productname>systemd</productname> + </refentryinfo> + + <refmeta> + <refentrytitle>systemd.swap</refentrytitle> + <manvolnum>5</manvolnum> + </refmeta> + + <refnamediv> + <refname>systemd.swap</refname> + <refpurpose>Swap unit configuration</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <para><filename><replaceable>swap</replaceable>.swap</filename></para> + </refsynopsisdiv> + + <refsect1> + <title>Description</title> + + <para>A unit configuration file whose name ends in + <literal>.swap</literal> encodes information about a swap device + or file for memory paging controlled and supervised by + systemd.</para> + + <para>This man page lists the configuration options specific to + this unit type. See + <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry> + for the common options of all unit configuration files. The common + configuration items are configured in the generic [Unit] and + [Install] sections. The swap specific configuration options are + configured in the [Swap] section.</para> + + <para>Additional options are listed in + <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>, + which define the execution environment the <citerefentry + project='man-pages'><refentrytitle>swapon</refentrytitle><manvolnum>8</manvolnum></citerefentry> + program is executed in, in + <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>, + which define the way these processes are + terminated, and in + <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>, + which configure resource control settings for these processes of the + unit.</para> + + <para>Swap units must be named after the devices or files they control. Example: the swap device <filename + index="false">/dev/sda5</filename> must be configured in a unit file <filename>dev-sda5.swap</filename>. For + details about the escaping logic used to convert a file system path to a unit name, see + <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>. Note that swap + units cannot be templated, nor is possible to add multiple names to a swap unit by creating additional symlinks to + it.</para> + + <para>Note that swap support on Linux is privileged, swap units are hence only available in the system + service manager (and root's user service manager), but not in unprivileged user's service manager.</para> + </refsect1> + + <refsect1> + <title>Automatic Dependencies</title> + + <refsect2> + <title>Implicit Dependencies</title> + + <para>The following dependencies are implicitly added:</para> + + <itemizedlist> + <listitem><para>All swap units automatically get the + <varname>BindsTo=</varname> and <varname>After=</varname> + dependencies on the device units or the mount units of the files + they are activated from.</para></listitem> + </itemizedlist> + + <para>Additional implicit dependencies may be added as result of + execution and resource control parameters as documented in + <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry> + and + <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para> + </refsect2> + + <refsect2> + <title>Default Dependencies</title> + + <para>The following dependencies are added unless <varname>DefaultDependencies=no</varname> is set:</para> + + <itemizedlist> + <listitem><para>Swap units automatically acquire a <varname>Conflicts=</varname> and a + <varname>Before=</varname> dependency on <filename>umount.target</filename> so that they are deactivated at + shutdown as well as a <varname>Before=swap.target</varname> dependency.</para></listitem> + </itemizedlist> + </refsect2> + </refsect1> + + <refsect1> + <title><filename>fstab</filename></title> + + <para>Swap units may either be configured via unit files, or via + <filename>/etc/fstab</filename> (see + <citerefentry project='man-pages'><refentrytitle>fstab</refentrytitle><manvolnum>5</manvolnum></citerefentry> + for details). Swaps listed in <filename>/etc/fstab</filename> will + be converted into native units dynamically at boot and when the + configuration of the system manager is reloaded. See + <citerefentry><refentrytitle>systemd-fstab-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry> + for details about the conversion.</para> + + <para>If a swap device or file is configured in both + <filename>/etc/fstab</filename> and a unit file, the configuration + in the latter takes precedence.</para> + + <para>When reading <filename>/etc/fstab</filename>, a few special + options are understood by systemd which influence how dependencies + are created for swap units.</para> + + <variablelist class='fstab-options'> + <varlistentry> + <term><option>noauto</option></term> + <term><option>auto</option></term> + + <listitem><para>With <option>noauto</option>, the swap unit + will not be added as a dependency for + <filename>swap.target</filename>. This means that it will not + be activated automatically during boot, unless it is pulled in + by some other unit. The <option>auto</option> option has the + opposite meaning and is the default.</para> + + <xi:include href="version-info.xml" xpointer="v218"/> + </listitem> + </varlistentry> + + <varlistentry> + <term><option>nofail</option></term> + + <listitem><para>With <option>nofail</option>, the swap unit + will be only wanted, not required by + <filename>swap.target</filename>. This means that the boot + will continue even if this swap device is not activated + successfully.</para> + + <xi:include href="version-info.xml" xpointer="v218"/> + </listitem> + </varlistentry> + + <xi:include href="systemd.mount.xml" xpointer="device-timeout" /> + + <varlistentry> + <term><option>x-systemd.makefs</option></term> + + <listitem><para>The swap structure will be initialized on the device. If the device is not + "empty", i.e. it contains any signature, the operation will be skipped. It is hence expected + that this option remains set even after the device has been initialized.</para> + + <para>Note that this option can only be used in <filename>/etc/fstab</filename>, and will be + ignored when part of the <varname>Options=</varname> setting in a unit file.</para> + + <para>See + <citerefentry><refentrytitle>systemd-mkswap@.service</refentrytitle><manvolnum>8</manvolnum></citerefentry> + and the discussion of + <citerefentry project='man-pages'><refentrytitle>wipefs</refentrytitle><manvolnum>8</manvolnum></citerefentry> + in <citerefentry><refentrytitle>systemd.mount</refentrytitle><manvolnum>5</manvolnum></citerefentry>. + </para> + + <xi:include href="version-info.xml" xpointer="v240"/></listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Options</title> + + <para>Swap unit files may include [Unit] and [Install] sections, which are described in + <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>. + </para> + + <para>Swap unit files must include a [Swap] section, which carries + information about the swap device it supervises. A number of + options that may be used in this section are shared with other + unit types. These options are documented in + <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry> + and + <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>. + The options specific to the [Swap] section of swap units are the + following:</para> + + <variablelist class='unit-directives'> + + <varlistentry> + <term><varname>What=</varname></term> + <listitem><para>Takes an absolute path of a device node or file to use for paging. See <citerefentry + project='man-pages'><refentrytitle>swapon</refentrytitle><manvolnum>8</manvolnum></citerefentry> for + details. If this refers to a device node, a dependency on the respective device unit is automatically + created. (See + <citerefentry><refentrytitle>systemd.device</refentrytitle><manvolnum>5</manvolnum></citerefentry> + for more information.) If this refers to a file, a dependency on the respective mount unit is + automatically created. (See + <citerefentry><refentrytitle>systemd.mount</refentrytitle><manvolnum>5</manvolnum></citerefentry> for + more information.) This option is mandatory. Note that the usual specifier expansion is applied to + this setting, literal percent characters should hence be written as + <literal class='specifiers'>%%</literal>.</para></listitem> + </varlistentry> + + <varlistentry> + <term><varname>Priority=</varname></term> + + <listitem><para>Swap priority to use when activating the swap + device or file. This takes an integer. This setting is + optional and ignored when the priority is set by <option>pri=</option> in the + <varname>Options=</varname> key.</para></listitem> + </varlistentry> + + <varlistentry> + <term><varname>Options=</varname></term> + + <listitem><para>May contain an option string for the swap device. This may be used for controlling discard + options among other functionality, if the swap backing device supports the discard or trim operation. (See + <citerefentry project='man-pages'><refentrytitle>swapon</refentrytitle><manvolnum>8</manvolnum></citerefentry> + for more information.) Note that the usual specifier expansion is applied to this setting, literal percent + characters should hence be written as <literal>%%</literal>.</para> + + <xi:include href="version-info.xml" xpointer="v217"/></listitem> + </varlistentry> + + <varlistentry> + <term><varname>TimeoutSec=</varname></term> + <listitem><para>Configures the time to wait for the swapon + command to finish. If a command does not exit within the + configured time, the swap will be considered failed and be + shut down again. All commands still running will be terminated + forcibly via <constant>SIGTERM</constant>, and after another + delay of this time with <constant>SIGKILL</constant>. (See + <option>KillMode=</option> in + <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>.) + Takes a unit-less value in seconds, or a time span value such + as "5min 20s". Pass <literal>0</literal> to disable the + timeout logic. Defaults to + <varname>DefaultTimeoutStartSec=</varname> from the manager + configuration file (see + <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>). + </para></listitem> + </varlistentry> + </variablelist> + + <xi:include href="systemd.service.xml" xpointer="shared-unit-options" /> + </refsect1> + + <refsect1> + <title>See Also</title> + <para> + <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, + <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>, + <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>, + <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>, + <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>, + <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>, + <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>, + <citerefentry><refentrytitle>systemd.device</refentrytitle><manvolnum>5</manvolnum></citerefentry>, + <citerefentry><refentrytitle>systemd.mount</refentrytitle><manvolnum>5</manvolnum></citerefentry>, + <citerefentry project='man-pages'><refentrytitle>swapon</refentrytitle><manvolnum>8</manvolnum></citerefentry>, + <citerefentry><refentrytitle>systemd-fstab-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>, + <citerefentry><refentrytitle>systemd.directives</refentrytitle><manvolnum>7</manvolnum></citerefentry> + </para> + </refsect1> + +</refentry> |