systemd.swap — systemd swap configuration files
systemd.swap
A unit configuration file whose name ends in
.swap
encodes information about a
swap device or file for memory paging controlled and
supervised by systemd.
This man page lists the configuration options specific to this unit type. See systemd.unit(5) 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.
Swap units must be named after the devices they
control. Example: the swap device
/dev/sda5
must be configured in a
unit file dev-sda5.swap
. For
details about the escaping logic used to convert a
file system path to a unit name see
systemd.unit(5).
fstab
Swap units may either be configured via unit
files, or via /etc/fstab
(see
fstab(5)
for details).
If a swap device or file is configured in both
/etc/fstab
and a unit file the
configuration in the latter takes precedence.
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 systemd.exec(5). The options specific to the [Swap] section of swap units are the following:
What=
Takes an absolute path of a device node or file to use for paging. See swapon(8) for details. If this refers to a device node, a dependency on the respective device unit is automatically created. (See systemd.device(5) for more information.) If this refers to a file, a dependency on the respective mount unit is automatically created. (See systemd.mount(5) for more information.) This option is mandatory.
Priority=
Swap priority to use when activating the swap device or file. This takes an integer. This setting is optional.
TimeoutSec=
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
KillMode=
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
60s.
KillMode=
Specifies how
processes of this swap shall be
killed. One of
control-group
,
process-group
,
process
,
none
.
This option is mostly equivalent
to the KillMode=
option of service files. See
systemd.service(5)
for details.
KillSignal=
Specifies which signal to use when killing a process of this swap. Defaults to SIGTERM.
SendSIGKILL=
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".