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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" | |
798d3a52 | 4 | "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"> |
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5 | |
6 | <!-- | |
7 | This file is part of systemd. | |
8 | ||
9 | Copyright 2010 Lennart Poettering | |
10 | ||
11 | systemd is free software; you can redistribute it and/or modify it | |
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12 | under the terms of the GNU Lesser General Public License as published by |
13 | the Free Software Foundation; either version 2.1 of the License, or | |
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14 | (at your option) any later version. |
15 | ||
16 | systemd is distributed in the hope that it will be useful, but | |
17 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
18 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
5430f7f2 | 19 | Lesser General Public License for more details. |
e0cabd4b | 20 | |
5430f7f2 | 21 | You should have received a copy of the GNU Lesser General Public License |
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22 | along with systemd; If not, see <http://www.gnu.org/licenses/>. |
23 | --> | |
24 | ||
25 | <refentry id="systemd.swap"> | |
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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>Swap unit configuration</refpurpose> | |
48 | </refnamediv> | |
49 | ||
50 | <refsynopsisdiv> | |
51 | <para><filename><replaceable>swap</replaceable>.swap</filename></para> | |
52 | </refsynopsisdiv> | |
53 | ||
54 | <refsect1> | |
55 | <title>Description</title> | |
56 | ||
57 | <para>A unit configuration file whose name ends in | |
58 | <literal>.swap</literal> encodes information about a swap device | |
59 | or file for memory paging controlled and supervised by | |
60 | systemd.</para> | |
61 | ||
62 | <para>This man page lists the configuration options specific to | |
63 | this unit type. See | |
64 | <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry> | |
65 | for the common options of all unit configuration files. The common | |
66 | configuration items are configured in the generic [Unit] and | |
67 | [Install] sections. The swap specific configuration options are | |
68 | configured in the [Swap] section.</para> | |
69 | ||
70 | <para>Additional options are listed in | |
71 | <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>, | |
72 | which define the execution environment the | |
73 | <citerefentry><refentrytitle>swapon</refentrytitle><manvolnum>8</manvolnum></citerefentry> | |
74 | binary is executed in, and in | |
75 | <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>, | |
76 | which define the way the processes are terminated, and in | |
77 | <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>, | |
78 | which configure resource control settings for the processes of the | |
79 | service.</para> | |
80 | ||
81 | <para>Swap units must be named after the devices | |
82 | or files they control. Example: the swap device | |
83 | <filename noindex='true'>/dev/sda5</filename> must be configured in a | |
84 | unit file <filename>dev-sda5.swap</filename>. For details about | |
85 | the escaping logic used to convert a file system path to a unit | |
86 | name, see | |
87 | <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para> | |
88 | ||
89 | <para>All swap units automatically get the appropriate | |
90 | dependencies on the devices or on the mount points of the files | |
91 | they are activated from.</para> | |
92 | ||
93 | <para>Swap units with <varname>DefaultDependencies=</varname> | |
94 | enabled implicitly acquire a conflicting dependency to | |
95 | <filename>umount.target</filename> so that they are deactivated at | |
96 | shutdown.</para> | |
97 | </refsect1> | |
98 | ||
99 | <refsect1> | |
100 | <title><filename>fstab</filename></title> | |
101 | ||
102 | <para>Swap units may either be configured via unit files, or via | |
103 | <filename>/etc/fstab</filename> (see | |
104 | <citerefentry><refentrytitle>fstab</refentrytitle><manvolnum>5</manvolnum></citerefentry> | |
105 | for details). Swaps listed in <filename>/etc/fstab</filename> will | |
106 | be converted into native units dynamically at boot and when the | |
107 | configuration of the system manager is reloaded. See | |
108 | <citerefentry><refentrytitle>systemd-fstab-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry> | |
109 | for details about the conversion.</para> | |
110 | ||
111 | <para>If a swap device or file is configured in both | |
112 | <filename>/etc/fstab</filename> and a unit file, the configuration | |
113 | in the latter takes precedence.</para> | |
114 | ||
115 | <para>When reading <filename>/etc/fstab</filename> a few special | |
116 | options are understood by systemd which influence how dependencies | |
117 | are created for swap units.</para> | |
118 | ||
119 | <variablelist class='fstab-options'> | |
120 | <varlistentry> | |
121 | <term><option>noauto</option></term> | |
122 | <term><option>auto</option></term> | |
123 | ||
124 | <listitem><para>With <option>noauto</option> the swap unit | |
125 | will not be added as a dependency for | |
126 | <filename>swap.target</filename>. This means that it will not | |
127 | be activated automatically during boot, unless it is pulled in | |
128 | by some other unit. Option <option>auto</option> has the | |
129 | opposite meaning and is the default.</para> | |
130 | </listitem> | |
131 | </varlistentry> | |
132 | ||
133 | <varlistentry> | |
134 | <term><option>nofail</option></term> | |
135 | ||
136 | <listitem><para>With <option>nofail</option> the swap unit | |
137 | will be only wanted, not required by | |
138 | <filename>swap.target</filename>. This means that the boot | |
139 | will continue even if this swap device is not activated | |
140 | successfully.</para> | |
141 | </listitem> | |
142 | </varlistentry> | |
143 | </variablelist> | |
144 | </refsect1> | |
145 | ||
146 | <refsect1> | |
147 | <title>Options</title> | |
148 | ||
149 | <para>Swap files must include a [Swap] section, which carries | |
150 | information about the swap device it supervises. A number of | |
151 | options that may be used in this section are shared with other | |
152 | unit types. These options are documented in | |
153 | <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry> | |
154 | and | |
155 | <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>. | |
156 | The options specific to the [Swap] section of swap units are the | |
157 | following:</para> | |
158 | ||
159 | <variablelist class='unit-directives'> | |
160 | ||
161 | <varlistentry> | |
162 | <term><varname>What=</varname></term> | |
163 | <listitem><para>Takes an absolute path of a device node or | |
164 | file to use for paging. See | |
165 | <citerefentry><refentrytitle>swapon</refentrytitle><manvolnum>8</manvolnum></citerefentry> | |
166 | for details. If this refers to a device node, a dependency on | |
167 | the respective device unit is automatically created. (See | |
168 | <citerefentry><refentrytitle>systemd.device</refentrytitle><manvolnum>5</manvolnum></citerefentry> | |
169 | for more information.) If this refers to a file, a dependency | |
170 | on the respective mount unit is automatically created. (See | |
171 | <citerefentry><refentrytitle>systemd.mount</refentrytitle><manvolnum>5</manvolnum></citerefentry> | |
172 | for more information.) This option is | |
173 | mandatory.</para></listitem> | |
174 | </varlistentry> | |
175 | ||
176 | <varlistentry> | |
177 | <term><varname>Priority=</varname></term> | |
178 | ||
179 | <listitem><para>Swap priority to use when activating the swap | |
180 | device or file. This takes an integer. This setting is | |
181 | optional.</para></listitem> | |
182 | </varlistentry> | |
183 | ||
184 | <varlistentry> | |
185 | <term><varname>Options=</varname></term> | |
186 | ||
187 | <listitem><para>May contain an option string for the swap | |
188 | device. This may be used for controlling discard options among | |
189 | other functionality, if the swap backing device supports the | |
190 | discard or trim operation. (See | |
191 | <citerefentry><refentrytitle>swapon</refentrytitle><manvolnum>8</manvolnum></citerefentry> | |
192 | for more information.) </para></listitem> | |
193 | </varlistentry> | |
194 | ||
195 | <varlistentry> | |
196 | <term><varname>TimeoutSec=</varname></term> | |
197 | <listitem><para>Configures the time to wait for the swapon | |
198 | command to finish. If a command does not exit within the | |
199 | configured time, the swap will be considered failed and be | |
200 | shut down again. All commands still running will be terminated | |
201 | forcibly via <constant>SIGTERM</constant>, and after another | |
202 | delay of this time with <constant>SIGKILL</constant>. (See | |
203 | <option>KillMode=</option> in | |
204 | <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>.) | |
205 | Takes a unit-less value in seconds, or a time span value such | |
206 | as "5min 20s". Pass <literal>0</literal> to disable the | |
207 | timeout logic. Defaults to | |
208 | <varname>DefaultTimeoutStartSec=</varname> from the manager | |
209 | configuration file (see | |
210 | <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>). | |
211 | </para></listitem> | |
212 | </varlistentry> | |
213 | </variablelist> | |
214 | ||
215 | <para>Check | |
216 | <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry> | |
217 | and | |
218 | <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry> | |
219 | for more settings.</para> | |
220 | </refsect1> | |
221 | ||
222 | <refsect1> | |
223 | <title>See Also</title> | |
224 | <para> | |
225 | <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, | |
226 | <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>, | |
227 | <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>, | |
228 | <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>, | |
229 | <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>, | |
230 | <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>, | |
231 | <citerefentry><refentrytitle>systemd.device</refentrytitle><manvolnum>5</manvolnum></citerefentry>, | |
232 | <citerefentry><refentrytitle>systemd.mount</refentrytitle><manvolnum>5</manvolnum></citerefentry>, | |
233 | <citerefentry><refentrytitle>swapon</refentrytitle><manvolnum>8</manvolnum></citerefentry>, | |
234 | <citerefentry><refentrytitle>systemd-fstab-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>, | |
235 | <citerefentry><refentrytitle>systemd.directives</refentrytitle><manvolnum>7</manvolnum></citerefentry> | |
236 | </para> | |
237 | </refsect1> | |
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238 | |
239 | </refentry> |