ZRAMCTL(8)                  System Administration                 ZRAMCTL(8)

NAME         top

       zramctl - set up and control zram devices

SYNOPSIS         top

       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         top

       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 zram devices are shown.

OPTIONS         top

       -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.

RETURN VALUE         top

       zramctl returns 0 on success, nonzero on failure.

FILES         top

              zram block devices

EXAMPLE         top

       The following commands set up a zram device with a size of one
       gigabyte and use it as swap device.

              # zramctl --find --size 1024M
              # mkswap /dev/zram0
              # swapon /dev/zram0
              # swapoff /dev/zram0
              # zramctl --reset /dev/zram0

SEE ALSO         top

       Linux kernel documentation 

AUTHORS         top

       Timofey Titovets <>
       Karel Zak <>

AVAILABILITY         top

       The zramctl command is part of the util-linux package and is
       available from

COLOPHON         top

       This page is part of the util-linux (a random collection of Linux
       utilities) project.  Information about the project can be found at 
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util-linux                        July 2014                       ZRAMCTL(8)