DescriptionA unit configuration file whose name ends in
- .swap encodes information about a
+ .swap encodes information about a
swap device or file for memory paging controlled and
supervised by systemd.
@@ -73,16 +73,19 @@
which define the execution environment the
swapon8
binary is executed in, and in
- systemd.kill5
+ systemd.kill5,
which define the way the processes are
- terminated.
+ terminated, and in
+ systemd.resource-control5,
+ which configure resource control settings for the
+ processes of the service.
Swap units must be named after the devices
or files 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
+ file system path to a unit name, see
systemd.unit5.All swap units automatically get the appropriate
@@ -111,15 +114,43 @@
for details about the conversion.If a swap device or file is configured in both
- /etc/fstab and a unit file the
+ /etc/fstab and a unit file, the
configuration in the latter takes precedence.
- Unless the option is set
- for them all swap units configured in
- /etc/fstab are also added as
- requirements to swap.target, so
- that they are waited for and activated during
- boot.
+ When reading /etc/fstab a
+ few special options are understood by systemd which
+ influence how dependencies are created for swap
+ units.
+
+
+
+
+
+
+ With the
+ swap unit will not be added as a dependency for
+ swap.target. This means that
+ it will not be activated automatically during
+ boot, unless it is pulled in by some other
+ unit. Option has the
+ opposite meaning and is the default.
+
+
+
+
+
+
+
+ With the
+ swap unit will be only wanted, not required by
+ swap.target. This means that
+ the boot will continue even if this swap device is
+ not activated successfully. Option
+ has the opposite meaning and
+ is the default.
+
+
+
@@ -167,24 +198,40 @@
setting is optional.
+
+ Options=
+
+ May contain an option
+ string for the swap device. This may
+ be used for controlling discard
+ options among other functionality, if
+ the swap backing device supports the
+ discard or trim operation. (See
+ swapon8
+ for more information.)
+
+
+
TimeoutSec=Configures the time to
wait for the swapon command to
finish. If a command does not exit
- within the configured time the swap
+ 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
+ SIGTERM, and after another delay of
+ this time with SIGKILL. (See
in
systemd.kill5.)
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.
+ 20s". Pass 0 to disable the timeout
+ logic. Defaults to DefaultTimeoutStartSec= from the
+ manager configuration file
+ (see systemd-system.conf5).
+
@@ -199,10 +246,11 @@
See Alsosystemd1,
- systemctl8,
+ systemctl1,
systemd.unit5,
systemd.exec5,
systemd.kill5,
+ systemd.resource-control5,
systemd.device5,
systemd.mount5,
swapon8,