systemd/man/systemd.swap.html
2014-04-27 12:02:08 +02:00

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<html><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><title>systemd.swap</title><meta name="generator" content="DocBook XSL Stylesheets V1.78.1"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><style>
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<a href="../libudev/index.html">gudev </a><span style="float:right">systemd 208</span><hr><div class="refentry"><a name="systemd.swap"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>systemd.swap — Swap unit configuration</p></div><div class="refsynopsisdiv"><h2>Synopsis</h2><p><code class="filename"><em class="replaceable"><code>swap</code></em>.swap</code></p></div><div class="refsect1"><a name="idm274701352320"></a><h2 id="Description">Description<a class="headerlink" title="Permalink to this headline" href="#Description"></a></h2><p>A unit configuration file whose name ends in
"<code class="literal">.swap</code>" encodes information about a
swap device or file for memory paging controlled and
supervised by systemd.</p><p>This man page lists the configuration options
specific to this unit type. See
<a href="systemd.unit.html"><span class="citerefentry"><span class="refentrytitle">systemd.unit</span>(5)</span></a>
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.</p><p>Additional options are listed in
<a href="systemd.exec.html"><span class="citerefentry"><span class="refentrytitle">systemd.exec</span>(5)</span></a>,
which define the execution environment the
<a href="swapon.html"><span class="citerefentry"><span class="refentrytitle">swapon</span>(8)</span></a>
binary is executed in, and in
<a href="systemd.kill.html"><span class="citerefentry"><span class="refentrytitle">systemd.kill</span>(5)</span></a>,
which define the way the processes are
terminated, and in
<a href="systemd.resource-control.html"><span class="citerefentry"><span class="refentrytitle">systemd.resource-control</span>(5)</span></a>,
which configure resource control settings for the
processes of the service.</p><p>Swap units must be named after the devices
or files they control. Example: the swap device
<code class="filename">/dev/sda5</code> must be configured in a
unit file <code class="filename">dev-sda5.swap</code>. For
details about the escaping logic used to convert a
file system path to a unit name see
<a href="systemd.unit.html"><span class="citerefentry"><span class="refentrytitle">systemd.unit</span>(5)</span></a>.</p><p>All swap units automatically get the appropriate
dependencies on the devices or on the mount points
of the files they are activated from.</p><p>Swap units with
<code class="varname">DefaultDependencies=</code> enabled
implicitly acquire a conflicting dependency to
<code class="filename">umount.target</code> so that they are
deactivated at shutdown.</p></div><div class="refsect1"><a name="idm274701216896"></a><h2 id="fstab"><code class="filename">fstab</code><a class="headerlink" title="Permalink to this headline" href="#fstab"></a></h2><p>Swap units may either be configured via unit
files, or via <code class="filename">/etc/fstab</code> (see
<a href="fstab.html"><span class="citerefentry"><span class="refentrytitle">fstab</span>(5)</span></a>
for details). Swaps listed in
<code class="filename">/etc/fstab</code> will be converted into
native units dynamically at boot and when the
configuration of the system manager is
reloaded. See
<a href="systemd-fstab-generator.html"><span class="citerefentry"><span class="refentrytitle">systemd-fstab-generator</span>(8)</span></a>
for details about the conversion.</p><p>If a swap device or file is configured in both
<code class="filename">/etc/fstab</code> and a unit file, the
configuration in the latter takes precedence.</p><p>Unless the <code class="option">noauto</code> option is set
for them all swap units configured in
<code class="filename">/etc/fstab</code> are also added as
requirements to <code class="filename">swap.target</code>, so
that they are waited for and activated during
boot.</p></div><div class="refsect1"><a name="idm274701407808"></a><h2 id="Options">Options<a class="headerlink" title="Permalink to this headline" href="#Options"></a></h2><p>Swap 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
<a href="systemd.exec.html"><span class="citerefentry"><span class="refentrytitle">systemd.exec</span>(5)</span></a>
and
<a href="systemd.kill.html"><span class="citerefentry"><span class="refentrytitle">systemd.kill</span>(5)</span></a>. The
options specific to the [Swap] section of swap units
are the following:</p><div class="variablelist"><dl class="variablelist"><dt id="What="><span class="term"><code class="varname">What=</code></span><a class="headerlink" title="Permalink to this term" href="#What="></a></dt><dd><p>Takes an absolute path
of a device node or file to use for
paging. See
<a href="swapon.html"><span class="citerefentry"><span class="refentrytitle">swapon</span>(8)</span></a>
for details. If this refers to a
device node, a dependency on the
respective device unit is
automatically created. (See
<a href="systemd.device.html"><span class="citerefentry"><span class="refentrytitle">systemd.device</span>(5)</span></a>
for more information.) If this refers
to a file, a dependency on the
respective mount unit is automatically
created. (See
<a href="systemd.mount.html"><span class="citerefentry"><span class="refentrytitle">systemd.mount</span>(5)</span></a>
for more information.) This option is
mandatory.</p></dd><dt id="Priority="><span class="term"><code class="varname">Priority=</code></span><a class="headerlink" title="Permalink to this term" href="#Priority="></a></dt><dd><p>Swap priority to use
when activating the swap device or
file. This takes an integer. This
setting is optional.</p></dd><dt id="TimeoutSec="><span class="term"><code class="varname">TimeoutSec=</code></span><a class="headerlink" title="Permalink to this term" href="#TimeoutSec="></a></dt><dd><p>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
<code class="constant">SIGTERM</code>, and after another delay of
this time with <code class="constant">SIGKILL</code>. (See
<code class="option">KillMode=</code> in
<a href="systemd.kill.html"><span class="citerefentry"><span class="refentrytitle">systemd.kill</span>(5)</span></a>.)
Takes a unit-less value in seconds, or
a time span value such as "5min
20s". Pass 0 to disable the timeout
logic. Defaults to
90s.</p></dd></dl></div><p>Check
<a href="systemd.exec.html"><span class="citerefentry"><span class="refentrytitle">systemd.exec</span>(5)</span></a>
and
<a href="systemd.kill.html"><span class="citerefentry"><span class="refentrytitle">systemd.kill</span>(5)</span></a>
for more settings.</p></div><div class="refsect1"><a name="idm274701383664"></a><h2 id="See Also">See Also<a class="headerlink" title="Permalink to this headline" href="#See%20Also"></a></h2><p>
<a href="systemd.html"><span class="citerefentry"><span class="refentrytitle">systemd</span>(1)</span></a>,
<a href="systemctl.html"><span class="citerefentry"><span class="refentrytitle">systemctl</span>(8)</span></a>,
<a href="systemd.unit.html"><span class="citerefentry"><span class="refentrytitle">systemd.unit</span>(5)</span></a>,
<a href="systemd.exec.html"><span class="citerefentry"><span class="refentrytitle">systemd.exec</span>(5)</span></a>,
<a href="systemd.kill.html"><span class="citerefentry"><span class="refentrytitle">systemd.kill</span>(5)</span></a>,
<a href="systemd.resource-control.html"><span class="citerefentry"><span class="refentrytitle">systemd.resource-control</span>(5)</span></a>,
<a href="systemd.device.html"><span class="citerefentry"><span class="refentrytitle">systemd.device</span>(5)</span></a>,
<a href="systemd.mount.html"><span class="citerefentry"><span class="refentrytitle">systemd.mount</span>(5)</span></a>,
<a href="swapon.html"><span class="citerefentry"><span class="refentrytitle">swapon</span>(8)</span></a>,
<a href="systemd-fstab-generator.html"><span class="citerefentry"><span class="refentrytitle">systemd-fstab-generator</span>(8)</span></a>,
<a href="systemd.directives.html"><span class="citerefentry"><span class="refentrytitle">systemd.directives</span>(7)</span></a>
</p></div></div></body></html>