summaryrefslogtreecommitdiff
path: root/man/systemd.swap.xml
blob: 954e94412f4a21dd4792f5f8ce99fc6bc0dec987 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
<?xml version='1.0'?> <!--*-nxml-*-->
<?xml-stylesheet type="text/xsl" href="http://docbook.sourceforge.net/release/xsl/current/xhtml/docbook.xsl"?>
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
        "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">

<!--
  This file is part of systemd.

  Copyright 2010 Lennart Poettering

  systemd is free software; you can redistribute it and/or modify it
  under the terms of the GNU General Public License as published by
  the Free Software Foundation; either version 2 of the License, or
  (at your option) any later version.

  systemd is distributed in the hope that it will be useful, but
  WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with systemd; If not, see <http://www.gnu.org/licenses/>.
-->

<refentry id="systemd.swap">
        <refentryinfo>
                <title>systemd.swap</title>
                <productname>systemd</productname>

                <authorgroup>
                        <author>
                                <contrib>Developer</contrib>
                                <firstname>Lennart</firstname>
                                <surname>Poettering</surname>
                                <email>lennart@poettering.net</email>
                        </author>
                </authorgroup>
        </refentryinfo>

        <refmeta>
                <refentrytitle>systemd.swap</refentrytitle>
                <manvolnum>5</manvolnum>
        </refmeta>

        <refnamediv>
                <refname>systemd.swap</refname>
                <refpurpose>systemd swap configuration files</refpurpose>
        </refnamediv>

        <refsynopsisdiv>
                <para><filename>systemd.swap</filename></para>
        </refsynopsisdiv>

        <refsect1>
                <title>Description</title>

                <para>A unit configuration file whose name ends in
                <filename>.swap</filename> 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>Swap units must be named after the devices
                (resp. files) they control. Example: the swap device
                <filename>/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>.</para>

                <para>All swap units automatically get the appropriate
                dependencies on the devices (resp. on the mount points
                of the files) they are actived from.</para>

                <para>Swap units with
                <varname>DefaultDependencies=</varname> enabled
                implicitly acquire a conflicting dependency to
                <filename>umount.target</filename> so that they are
                deactivated at shutdown.</para>
        </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><refentrytitle>fstab</refentrytitle><manvolnum>5</manvolnum></citerefentry>
                for details).</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>Unless the <option>noauto</option> option is set
                for them all swap units configured in
                <filename>/etc/fstab</filename> are also added as
                requirements to <filename>swap.target</filename>, so
                that they are waited for and activated during
                boot.</para>
        </refsect1>

        <refsect1>
                <title>Options</title>

                <para>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
                <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>. The
                options specific to the [Swap] section of swap units
                are the following:</para>

                <variablelist>

                        <varlistentry>
                                <term><varname>What=</varname></term>
                                <listitem><para>Takes an absolute path
                                of a device node or file to use for
                                paging. See
                                <citerefentry><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.</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.</para></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
                                SIGTERM, and after another delay of
                                this time with SIGKILL. (See
                                <option>KillMode=</option> below.)
                                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.</para></listitem>
                        </varlistentry>

                        <varlistentry>
                                <term><varname>KillMode=</varname></term>
                                <listitem><para>Specifies how
                                processes of this swap shall be
                                killed. One of
                                <option>control-group</option>,
                                <option>process</option>,
                                <option>none</option>.</para>

                                <para>This option is mostly equivalent
                                to the <option>KillMode=</option>
                                option of service files. See
                                <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>
                                for details.</para></listitem>
                        </varlistentry>

                        <varlistentry>
                                <term><varname>KillSignal=</varname></term>
                                <listitem><para>Specifies which signal
                                to use when killing a process of this
                                swap. Defaults to SIGTERM.
                                </para></listitem>
                        </varlistentry>

                        <varlistentry>
                                <term><varname>SendSIGKILL=</varname></term>
                                <listitem><para>Specifies whether to
                                send SIGKILL to remaining processes
                                after a timeout, if the normal
                                shutdown procedure left processes of
                                the swap around. Takes a boolean
                                value. Defaults to "yes".
                                </para></listitem>
                        </varlistentry>
                </variablelist>
        </refsect1>

        <refsect1>
                  <title>See Also</title>
                  <para>
                          <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
                          <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
                          <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
                          <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
                          <citerefentry><refentrytitle>systemd.device</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
                          <citerefentry><refentrytitle>systemd.mount</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
                          <citerefentry><refentrytitle>swapon</refentrytitle><manvolnum>8</manvolnum></citerefentry>
                  </para>
        </refsect1>

</refentry>