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1 <?xml version='1.0'?> <!--*-nxml-*-->
2 <?xml-stylesheet type="text/xsl" href="http://docbook.sourceforge.net/release/xsl/current/xhtml/docbook.xsl"?>
3 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
4         "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
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24
25 <refentry id="systemd.swap">
26         <refentryinfo>
27                 <title>systemd.swap</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.swap</refentrytitle>
42                 <manvolnum>5</manvolnum>
43         </refmeta>
44
45         <refnamediv>
46                 <refname>systemd.swap</refname>
47                 <refpurpose>systemd swap configuration files</refpurpose>
48         </refnamediv>
49
50         <refsynopsisdiv>
51                 <para><filename>systemd.swap</filename></para>
52         </refsynopsisdiv>
53
54         <refsect1>
55                 <title>Description</title>
56
57                 <para>A unit configuration file whose name ends in
58                 <filename>.swap</filename> encodes information about a
59                 swap device or file for memory paging controlled and
60                 supervised by 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 swap
68                 specific configuration options are configured in the
69                 [Swap] section.</para>
70
71                 <para>Swap units must be named after the devices they
72                 control. Example: the swap device
73                 <filename>/dev/sda5</filename> must be configured in a
74                 unit file <filename>dev-sda5.swap</filename>. For
75                 details about the escaping logic used to convert a
76                 file system path to a unit name see
77                 <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
78         </refsect1>
79
80         <refsect1>
81                 <title><filename>fstab</filename></title>
82
83                 <para>Swap units may either be configured via unit
84                 files, or via <filename>/etc/fstab</filename> (see
85                 <citerefentry><refentrytitle>fstab</refentrytitle><manvolnum>5</manvolnum></citerefentry>
86                 for details).</para>
87
88                 <para>If a swap device or file is configured in both
89                 <filename>/etc/fstab</filename> and a unit file the
90                 configuration in the latter takes precedence.</para>
91         </refsect1>
92
93         <refsect1>
94                 <title>Options</title>
95
96                 <para>Swap files must include a [Swap] section, which
97                 carries information about the swap device it
98                 supervises. The options specific to the [Swap] section
99                 of swap units are the following:</para>
100
101                 <variablelist>
102
103                         <varlistentry>
104                                 <term><varname>What=</varname></term>
105                                 <listitem><para>Takes an absolute path
106                                 of a device node or file to use for
107                                 paging. See
108                                 <citerefentry><refentrytitle>swapon</refentrytitle><manvolnum>8</manvolnum></citerefentry>
109                                 for details. If this refers to a
110                                 device node, a dependency on the
111                                 respective device unit is
112                                 automatically created. (See
113                                 <citerefentry><refentrytitle>systemd.device</refentrytitle><manvolnum>5</manvolnum></citerefentry>
114                                 for more information.) If this refers
115                                 to a file, a dependency on the
116                                 respective mount unit is automatically
117                                 created. (See
118                                 <citerefentry><refentrytitle>systemd.mount</refentrytitle><manvolnum>5</manvolnum></citerefentry>
119                                 for more information.) This option is
120                                 mandatory.</para></listitem>
121                         </varlistentry>
122
123                         <varlistentry>
124                                 <term><varname>Priority=</varname></term>
125
126                                 <listitem><para>Swap priority to use
127                                 when activating the swap device or
128                                 file. This takes an integer. This
129                                 setting is optional.</para></listitem>
130                         </varlistentry>
131                 </variablelist>
132         </refsect1>
133
134         <refsect1>
135                   <title>See Also</title>
136                   <para>
137                           <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
138                           <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
139                           <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
140                           <citerefentry><refentrytitle>systemd.device</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
141                           <citerefentry><refentrytitle>systemd.mount</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
142                           <citerefentry><refentrytitle>swapon</refentrytitle><manvolnum>8</manvolnum></citerefentry>
143                   </para>
144         </refsect1>
145
146 </refentry>