zramctl(8)

1ZRAMCTL(8)                   System Administration                  ZRAMCTL(8)
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NAME

6       zramctl - set up and control zram devices
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SYNOPSIS

9       Get info:
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11            zramctl [options]
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13       Reset zram:
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15            zramctl -r zramdev...
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17       Print name of first unused zram device:
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19            zramctl -f
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21       Set up a zram device:
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23            zramctl [-f | zramdev] [-s size] [-t number] [-a algorithm]
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DESCRIPTION

27       zramctl is used to quickly set up zram device parameters, to reset zram
28       devices, and to query the status of used zram devices.
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30       If no option is given, all non-zero size zram devices are shown.
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OPTIONS

33       -a, --algorithm lzo|lz4
34              Set the compression algorithm to be used for compressing data in
35              the zram device.
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37       -f, --find
38              Find  the  first  unused  zram  device.  If a --size argument is
39              present, then initialize the device.
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41       -n, --noheadings
42              Do not print a header line in status output.
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44       -o, --output list
45              Define the status output columns  to  be  used.   If  no  output
46              arrangement  is  specified,  then  a  default  set is used.  Use
47              --help to get a list of all supported columns.
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49       --raw  Use the raw format for status output.
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51       -r, --reset
52              Reset the options of the specified zram device(s).  Zram  device
53              settings can be changed only after a reset.
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55       -s, --size size
56              Create  a  zram  device of the specified size.  Zram devices are
57              aligned to memory pages; when the requested size is not a multi‐
58              ple  of  the page size, it will be rounded up to the next multi‐
59              ple.  When not otherwise specified, the unit of the size parame‐
60              ter is bytes.
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62              The size argument may be followed by the multiplicative suffixes
63              KiB (=1024), MiB (=1024*1024), and so on for GiB, TiB, PiB, EiB,
64              ZiB  and YiB (the "iB" is optional, e.g., "K" has the same mean‐
65              ing as "KiB") or the suffixes KB (=1000), MB  (=1000*1000),  and
66              so on for GB, TB, PB, EB, ZB and YB.
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68       -t, --streams number
69              Set  the  maximum number of compression streams that can be used
70              for the device.  The default is one stream.
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72       -V, --version
73              Display version information and exit.
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75       -h, --help
76              Display help text and exit.
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RETURN VALUE

80       zramctl returns 0 on success, nonzero on failure.
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FILES

84       /dev/zram[0..N]
85              zram block devices
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EXAMPLE

89       The following commands set up a zram device with a size of one gigabyte
90       and use it as swap device.
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92              # zramctl --find --size 1024M
93              /dev/zram0
94              # mkswap /dev/zram0
95              # swapon /dev/zram0
96               ...
97              # swapoff /dev/zram0
98              # zramctl --reset /dev/zram0
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AUTHORS

105       Timofey Titovets <nefelim4ag@gmail.com>
106       Karel Zak <kzak@redhat.com>
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AVAILABILITY

109       The zramctl command is part of the util-linux package and is  available
110       from https://www.kernel.org/pub/linux/utils/util-linux/.
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114util-linux                         July 2014                        ZRAMCTL(8)