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ZRAMCTL(8) System Administration ZRAMCTL(8)
zramctl - set up and control zram devices
Get info:
zramctl [options]
Reset zram:
zramctl -r zramdev...
Print name of first unused zram device:
zramctl -f
Set up a zram device:
zramctl [-f | zramdev] [-s size] [-t number] [-a algorithm]
zramctl is used to quickly set up zram device parameters, to reset
zram devices, and to query the status of used zram devices.
If no option is given, all non-zero size zram devices are shown.
-a, --algorithm lzo|lz4
Set the compression algorithm to be used for compressing data
in the zram device.
-f, --find
Find the first unused zram device. If a --size argument is
present, then initialize the device.
-n, --noheadings
Do not print a header line in status output.
-o, --output list
Define the status output columns to be used. If no output
arrangement is specified, then a default set is used. Use
--help to get a list of all supported columns.
--raw Use the raw format for status output.
-r, --reset
Reset the options of the specified zram device(s). Zram
device settings can be changed only after a reset.
-s, --size size
Create a zram device of the specified size. Zram devices are
aligned to memory pages; when the requested size is not a
multiple of the page size, it will be rounded up to the next
multiple. When not otherwise specified, the unit of the size
parameter is bytes.
The size argument may be followed by the multiplicative
suffixes KiB (=1024), MiB (=1024*1024), and so on for GiB,
TiB, PiB, EiB, ZiB and YiB (the "iB" is optional, e.g., "K"
has the same meaning as "KiB") or the suffixes KB (=1000), MB
(=1000*1000), and so on for GB, TB, PB, EB, ZB and YB.
-t, --streams number
Set the maximum number of compression streams that can be used
for the device. The default is one stream.
-V, --version
Display version information and exit.
-h, --help
Display help text and exit.
zramctl returns 0 on success, nonzero on failure.
/dev/zram[0..N]
zram block devices
The following commands set up a zram device with a size of one
gigabyte and use it as swap device.
# zramctl --find --size 1024M
/dev/zram0
# mkswap /dev/zram0
# swapon /dev/zram0
...
# swapoff /dev/zram0
# zramctl --reset /dev/zram0
Linux kernel documentation
⟨http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/Documentation/blockdev/zram.txt⟩.
Timofey Titovets <nefelim4ag@gmail.com>
Karel Zak <kzak@redhat.com>
The zramctl command is part of the util-linux package and is
available from https://www.kernel.org/pub/linux/utils/util-linux/.
This page is part of the util-linux (a random collection of Linux
utilities) project. Information about the project can be found at
⟨https://www.kernel.org/pub/linux/utils/util-linux/⟩. If you have a
bug report for this manual page, send it to
util-linux@vger.kernel.org. This page was obtained from the
project's upstream Git repository
⟨git://git.kernel.org/pub/scm/utils/util-linux/util-linux.git⟩ on
2017-07-05. If you discover any rendering problems in this HTML ver‐
sion of the page, or you believe there is a better or more up-to-date
source for the page, or you have corrections or improvements to the
information in this COLOPHON (which is not part of the original man‐
ual page), send a mail to man-pages@man7.org
util-linux July 2014 ZRAMCTL(8)