NAME¶systemd.swap - Swap unit configuration
DESCRIPTION¶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.
Additional options are listed in systemd.exec(5), which define the execution environment the swapon(8) binary is executed in, in systemd.kill(5), which define the way these processes are terminated, and in systemd.resource-control(5), which configure resource control settings for these processes of the unit.
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 systemd.unit(5). Note that swap units cannot be templated, nor is possible to add multiple names to a swap unit by creating additional symlinks to it.
AUTOMATIC DEPENDENCIES¶All swap units automatically get the BindsTo= and After= dependencies on the device units or the mount units of the files they are activated from.
Swap units with DefaultDependencies= in the "[Unit]" section enabled implicitly acquire a Conflicts= and an After= dependency on umount.target so that they are deactivated at shutdown, unless DefaultDependencies=no is specified.
FSTAB¶Swap units may either be configured via unit files, or via /etc/fstab (see fstab(5) for details). Swaps listed in /etc/fstab will be converted into native units dynamically at boot and when the configuration of the system manager is reloaded. See systemd-fstab-generator(8) for details about the conversion.
If a swap device or file is configured in both /etc/fstab and a unit file, the configuration in the latter takes precedence.
When reading /etc/fstab, a few special options are understood by systemd which influence how dependencies are created for swap units.
OPTIONS¶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) and systemd.kill(5). The options specific to the [Swap] section of swap units are the following:
SEE ALSO¶systemd(1), systemctl(1), systemd.unit(5), systemd.exec(5), systemd.kill(5), systemd.resource-control(5), systemd.device(5), systemd.mount(5), swapon(8), systemd-fstab-generator(8), systemd.directives(7)