uswsusp.conf - Config file for the s2disk program
This manual page documents briefly the uswsusp.conf file used by the
s2disk, s2both and resume commands.
This manual page was written for the Debian distribution because the
original program does not have a manual page.
s2disk is a program that will save the the state of the whole system to
disk and power off your system. After restarting your system it will
be put back in the exact system state you left it (this is sometimes
On a Debian system you can run dpkg-reconfigure uswsusp to manage this
snapshot device [=/dev/snapshot]
Device via which s2disk should talk to the kernel.
Specifies the device to write the image to. This is a swap
partition or the partition that contains the swap file (see next
Necessary if a swap file is used for suspending. In such a case
the device identified by the "resume device" parameter is
regarded as the partition that contains the swap file, and
"resume offset" must be equal to the offset from the beginning
of this partition at which the swap file's header is located, in
<PAGE_SIZE> units. The value of this parameter for given swap
file can be determined by the swap-offset program (has to be run
as root) included in this package. [For this feature to work,
you will need an -mm kernel, 2.6.18-mm3 or newer.]
Limit the size of the system snapshot image created by the
s2disk tool, but it's not mandatory. Namely, the s2disk tool
will do its best to limit the image size as required by this
parameter, but if that's not possible, it will suspend the
system anyway, with a bigger image. If "image size" is set to 0,
the snapshot image will be as small as possible.
You can specify the kernel console loglevel which the
s2disk/s2both and resume utilities will use to report progress.
On a stock kernel messages with level higher then 7 are usually
This parameter defines the operation that will be carried out
after the suspend image has been created and the machine is
ready to be powered off. If it is set to "reboot", the machine
will be rebooted immediately. If it is set to "platform", the
machine will be shut down using special power management
operations available from the kernel that may be necessary for
the hardware to be properly reinitialized after the resume, and
may cause the system to resume faster (this is the recommended
shutdown method on the majority of systems and hence the
defaul). If set to "shutdown" the machine will be powered off.
If the "compute checksum" parameter is set to 'y', the s2disk
and resume tools will use the MD5 algorithm to verify the image
If the "compress" parameter is set to 'y', the s2disk and resume
tools will use the LZF compression algorithm to
compress/decompress the image.
If the "encrypt" parameter is set to 'y', the s2disk and resume
tools will use the Blowfish encryption algorithm to
encrypt/decrypt the image. On resume and suspend you will have
to supply a passphrase. By using a pregenerated RSA key, you
can avoid having to type a passphrase on suspend. See the "RSA
key file" option for more information.
RSA key file
If this this options points a valid RSA key, which can be
created with suspend-keygen, the s2disk tool will generate a
random key for the Blowfish encryption that will be passed to
the resume tool within the image header with the help of the RSA
cipher. Consequently you only need to type a passphrase on
If the "early writeout" parameter is set to 'y' is specified,
the s2disk utility will start syncing the resume device early in
the process of writing the image to it. [This has been reported
to speed up the s2disk on some boxes and eliminates the "fast
progress meter and long fsync wait" effect.]
splash The "splash" parameter is used to make s2disk and/or resume use
a splash system (when set to 'y'). Currently the bootsplash.org
and splashy systems are supported. For the former you need a
kernel patch, the later is a userspace solution, but you'll need
to install a splashy theme.
If you use initramfs-tools on Debian to generate your initramfs
(and have splashy installed), the necessary files will be copied
s2disk (8). suspend-keygen(8)
This manual page was written by Tim Dijkstra <firstname.lastname@example.org> for
the Debian system (but may be used by others). Permission is granted to
copy, distribute and/or modify this document under the terms of the GNU
General Public License, Version 2 any later version published by the
Free Software Foundation.
On Debian systems, the complete text of the GNU General Public License
can be found in /usr/share/common-licenses/GPL.
juni 24, 2006 uswsusp.conf(8)