SYSTEMD-SLEEP.CONF(5) systemd-sleep.conf SYSTEMD-SLEEP.CONF(5)
NAME
systemd-sleep.conf, sleep.conf.d - Suspend and hibernation configuration
file
SYNOPSIS
/etc/systemd/sleep.conf
/run/systemd/sleep.conf
/usr/lib/systemd/sleep.conf
/etc/systemd/sleep.conf.d/*.conf
/run/systemd/sleep.conf.d/*.conf
/usr/lib/systemd/sleep.conf.d/*.conf
DESCRIPTION
systemd supports four general power-saving modes:
suspend
a low-power state where execution of the OS is paused, and complete
power loss might result in lost data, and which is fast to enter and
exit. This corresponds to suspend, standby, or freeze states as
understood by the kernel.
Added in version 203.
hibernate
a low-power state where execution of the OS is paused, and complete
power loss does not result in lost data, and which might be slow to
enter and exit. This corresponds to the hibernation as understood by
the kernel.
Added in version 203.
hybrid-sleep
a low-power state where execution of the OS is paused, which might
be slow to enter, and on complete power loss does not result in lost
data but might be slower to exit in that case. This mode is called
suspend-to-both by the kernel.
Added in version 203.
suspend-then-hibernate
A low power state where the system is initially suspended (the state
is stored in RAM). When the battery level is too low (less than 5%)
or a certain timespan has passed, whichever happens first, the
system is automatically woken up and then hibernated. This
establishes a balance between speed and safety.
If the system has no battery, it would be hibernated after
HibernateDelaySec= has passed. If not set, then defaults to "2h".
If the system has battery and HibernateDelaySec= is not set,
low-battery alarms (ACPI _BTP) are tried first for detecting battery
percentage and wake up the system for hibernation. If not available,
or HibernateDelaySec= is set, the system would regularly wake up to
check the time and detect the battery percentage/discharging rate.
The rate is used to schedule the next detection. If that is also not
available, SuspendEstimationSec= is used as last resort.
Added in version 239.
Settings in these files determine what strings will be written to
/sys/power/disk and /sys/power/state by systemd-sleep(8) when systemd(1)
attempts to suspend or hibernate the machine. See systemd.syntax(7) for
a general description of the syntax.
CONFIGURATION DIRECTORIES AND PRECEDENCE
The default configuration is set during compilation, so configuration is
only needed when it is necessary to deviate from those defaults. The
main configuration file is loaded from one of the listed directories in
order of priority, only the first file found is used: /etc/systemd/,
/run/systemd/, /usr/local/lib/systemd/ [1], /usr/lib/systemd/. The
vendor version of the file contains commented out entries showing the
defaults as a guide to the administrator. Local overrides can also be
created by creating drop-ins, as described below. The main configuration
file can also be edited for this purpose (or a copy in /etc/ if it is
shipped under /usr/), however using drop-ins for local configuration is
recommended over modifications to the main configuration file.
In addition to the main configuration file, drop-in configuration
snippets are read from /usr/lib/systemd/*.conf.d/,
/usr/local/lib/systemd/*.conf.d/, and /etc/systemd/*.conf.d/. Those
drop-ins have higher precedence and override the main configuration
file. Files in the *.conf.d/ configuration subdirectories are sorted by
their filename in lexicographic order, regardless of in which of the
subdirectories they reside. When multiple files specify the same option,
for options which accept just a single value, the entry in the file
sorted last takes precedence, and for options which accept a list of
values, entries are collected as they occur in the sorted files.
When packages need to customize the configuration, they can install
drop-ins under /usr/. Files in /etc/ are reserved for the local
administrator, who may use this logic to override the configuration
files installed by vendor packages. Drop-ins have to be used to override
package drop-ins, since the main configuration file has lower
precedence. It is recommended to prefix all filenames in those
subdirectories with a two-digit number and a dash, to simplify the
ordering. This also defines a concept of drop-in priorities to allow OS
vendors to ship drop-ins within a specific range lower than the range
used by users. This should lower the risk of package drop-ins overriding
accidentally drop-ins defined by users. It is recommended to use the
range 10-40 for drop-ins in /usr/ and the range 60-90 for drop-ins in
/etc/ and /run/, to make sure that local and transient drop-ins take
priority over drop-ins shipped by the OS vendor.
To disable a configuration file supplied by the vendor, the recommended
way is to place a symlink to /dev/null in the configuration directory in
/etc/, with the same filename as the vendor configuration file.
OPTIONS
The following options can be configured in the [Sleep] section of
/etc/systemd/sleep.conf or a sleep.conf.d file:
AllowSuspend=, AllowHibernation=, AllowHybridSleep=,
AllowSuspendThenHibernate=
By default, any power-saving mode is advertised if possible (i.e.
the kernel supports that mode, the necessary resources are
available). Those switches can be used to disable specific modes.
If AllowHibernation=no or AllowSuspend=no is used, this implies
AllowSuspendThenHibernate=no and AllowHybridSleep=no, since those
methods use both suspend and hibernation internally.
AllowSuspendThenHibernate=yes and AllowHybridSleep=yes can be used
to override and enable those specific modes.
Added in version 240.
SuspendState=
The string to be written to /sys/power/state by systemd-
suspend.service(8). More than one value can be specified by
separating multiple values with whitespace. They will be tried in
turn, until one is written without error. If none of the writes
succeed, the operation will be aborted.
The allowed set of values is determined by the kernel and is shown
in the file itself (use cat /sys/power/state to display). See Basic
sysfs Interfaces for System Suspend and Hibernation[2] for more
details.
systemd-suspend-then-hibernate.service(8) uses this value when
suspending.
Added in version 203.
HibernateMode=
The string to be written to /sys/power/disk by systemd-
hibernate.service(8). More than one value can be specified by
separating multiple values with whitespace. They will be tried in
turn, until one is written without error. If none of the writes
succeed, the operation will be aborted.
The allowed set of values is determined by the kernel and is shown
in the file itself (use cat /sys/power/disk to display). See the
kernel documentation page Basic sysfs Interfaces for System Suspend
and Hibernation[2] for more details.
systemd-suspend-then-hibernate.service(8) uses the value of
HibernateMode= when hibernating.
Added in version 203.
MemorySleepMode=
The string to be written to /sys/power/mem_sleep when
SuspendState=mem or hybrid-sleep is used. More than one value can be
specified by separating multiple values with whitespace. They will
be tried in turn, until one is written without error. If none of the
writes succeed, the operation will be aborted. Defaults to empty,
i.e. the kernel default or kernel command line option
mem_sleep_default= is respected.
The allowed set of values is determined by the kernel and is shown
in the file itself (use cat /sys/power/mem_sleep to display). See
the kernel documentation page Basic sysfs Interfaces for System
Suspend and Hibernation[2] for more details.
Added in version 256.
HibernateDelaySec=
The amount of time the system spends in suspend mode before the
system is automatically put into hibernate mode. Only used by
systemd-suspend-then-hibernate.service(8). Refer to
suspend-then-hibernate for details on how this option interacts with
other options/system battery state.
Added in version 239.
HibernateOnACPower=
Whether to allow hibernation when the system has AC power. Only used
by systemd-suspend-then-hibernate.service(8) when HibernateDelaySec=
is set.
If this option is disabled, the countdown of HibernateDelaySec=
starts only after AC power is disconnected, keeping the system in
the suspend state otherwise.
This option is only effective on systems with a battery.
Added in version 257.
SuspendEstimationSec=
The RTC alarm will wake the system after the specified timespan to
measure the system battery capacity level and estimate battery
discharging rate. Only used by systemd-suspend-then-
hibernate.service(8). Refer to suspend-then-hibernate for details on
how this option interacts with other options/system battery state.
Added in version 253.
EXAMPLE: FREEZE
Example: to exploit the “freeze” mode added in Linux 3.9, one can use
systemctl suspend with
[Sleep]
SuspendState=freeze
SEE ALSO
systemd-sleep(8), systemd-suspend.service(8), systemd-
hibernate.service(8), systemd-hybrid-sleep.service(8), systemd-suspend-
then-hibernate.service(8), systemd(1), systemd.directives(7)
NOTES
1. 💣💥🧨💥💥💣 Please note that those configuration files must be available
at all times. If /usr/local/ is a separate partition, it may not be
available during early boot, and must not be used for configuration.
2. Basic sysfs Interfaces for System Suspend and Hibernation
https://docs.kernel.org/admin-guide/pm/sleep-states.html#basic-sysfs-interfaces-for-system-suspend-and-hibernation
systemd 257.9 SYSTEMD-SLEEP.CONF(5)
Generated by dwww version 1.16 on Tue Dec 16 04:00:24 CET 2025.