zramctl

ZRAMCTL(8)                   System Administration                  ZRAMCTL(8)

NAME
       zramctl - set up and control zram devices

SYNOPSIS
       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]

DESCRIPTION
       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.

OPTIONS
       -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 multi-
              ple  of  the page size, it will be rounded up to the next multi-
              ple.  When not otherwise specified, the unit of the size parame-
              ter 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 mean-
              ing 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.

RETURN VALUE
       zramctl returns 0 on success, nonzero on failure.

FILES
       /dev/zram[0..N]
              zram block devices

EXAMPLE
       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

SEE ALSO
       Linux kernel documentation <http://git.kernel.org/cgit/linux/kernel/git
       /torvalds/linux.git/tree/Documentation/blockdev/zram.txt>.

AUTHORS
       Timofey Titovets <nefelim4ag@gmail.com>
       Karel Zak <kzak@redhat.com>

AVAILABILITY
       The zramctl command is part of the util-linux package and is  available
       from https://www.kernel.org/pub/linux/utils/util-linux/.

util-linux                         July 2014                        ZRAMCTL(8)
Man Pages Copyright Respective Owners. Site Copyright (C) 1994 - 2022 Hurricane Electric. All Rights Reserved.