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 called hibernation).
On a Debian system you can run dpkg-reconfigure uswsusp to manage this file.
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 parameter).
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
utilities will use to report progress. On a stock kernel messages with
level higher then 7 are usually not shown.
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 integrity.
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
the s2disk tool will generate a random
key for the Blowfish encryption that will be passed to the
within the image header with the help of the RSA cipher.
Consequently you only need to type a passphrase on resume.
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.]
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 to it.
This manual page was written by Tim Dijkstra <email@example.com> 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.