SYSTEMD.SWAP(5)                            systemd.swap                           SYSTEMD.SWAP(5)



NAME
       systemd.swap - Swap unit configuration

SYNOPSIS
       swap.swap

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, and in systemd.kill(5), which define the way the
       processes are terminated, and in systemd.resource-control(5), 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 systemd.unit(5).

       All swap units automatically get the appropriate dependencies on the devices or on the
       mount points of the files they are activated from.

       Swap units with DefaultDependencies= enabled implicitly acquire a conflicting dependency
       to umount.target so that they are deactivated at shutdown.

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.

       Unless the noauto 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.

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:

       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.

       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 swapon(8) 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 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= in systemd.kill(5).) 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 TimeoutStartSec= from the manager configuration file.

       Check systemd.exec(5) and systemd.kill(5) for more settings.

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)



systemd 215                                                                       SYSTEMD.SWAP(5)