sys-utils/zramctl.8

   1 .TH ZRAMCTL 8 "July 2014" "util-linux" "System Administration"
   2 .SH NAME
   3 zramctl \- set up and control zram devices
   4 .SH SYNOPSIS
   5 .ad l
   6 Get info:
   7 .sp
   8 .in +5
   9 .BR zramctl " [options]"
  10 .sp
  11 .in -5
  12 Reset zram:
  13 .sp
  14 .in +5
  15 .B "zramctl \-r"
  16 .IR zramdev ...
  17 .sp
  18 .in -5
  19 Print name of first unused zram device:
  20 .sp
  21 .in +5
  22 .B "zramctl \-f"
  23 .sp
  24 .in -5
  25 Set up a zram device:
  26 .sp
  27 .in +5
  28 .B zramctl
  29 .RB [ \-f " | "\fIzramdev\fP ]
  30 .RB [ \-s
  31 .IR size ]
  32 .RB [ \-t
  33 .IR number ]
  34 .RB [ \-a
  35 .IR algorithm ]
  36 .sp
  37 .in -5
  38 .ad b
  39 .SH DESCRIPTION
  40 .B zramctl
  41 is used to quickly set up zram device parameters, to reset zram devices, and to
  42 query the status of used zram devices.
  43 .PP
  44 If no option is given, all non-zero size zram devices are shown.
  45 .SH OPTIONS
  46 .TP
  47 .BR \-a , " \-\-algorithm lzo" | lz4 | lz4hc | deflate | 842
  48 Set the compression algorithm to be used for compressing data in the zram device.
  49 .TP
  50 .BR \-f , " \-\-find"
  51 Find the first unused zram device.  If a \fB--size\fR argument is present, then
  52 initialize the device.
  53 .TP
  54 .BR \-n , " \-\-noheadings"
  55 Do not print a header line in status output.
  56 .TP
  57 .BR \-o , " \-\-output " \fIlist
  58 Define the status output columns to be used.  If no output arrangement is
  59 specified, then a default set is used.
  60 Use \fB\-\-help\fP to get a list of all supported columns.
  61 .TP
  62 .B \-\-output\-all
  63 Output all available columns.
  64 .TP
  65 .B \-\-raw
  66 Use the raw format for status output.
  67 .TP
  68 .BR \-r , " \-\-reset"
  69 Reset the options of the specified zram device(s).  Zram device settings
  70 can be changed only after a reset.
  71 .TP
  72 .BR \-s , " \-\-size " \fIsize
  73 Create a zram device of the specified \fIsize\fR.
  74 Zram devices are aligned to memory pages; when the requested \fIsize\fR is
  75 not a multiple of the page size, it will be rounded up to the next multiple.
  76 When not otherwise specified, the unit of the \fIsize\fR parameter is bytes.
  77 .IP
  78 The \fIsize\fR argument may be followed by the multiplicative suffixes KiB (=1024),
  79 MiB (=1024*1024), and so on for GiB, TiB, PiB, EiB, ZiB and YiB (the "iB"
  80 is optional, e.g., "K" has the same meaning as "KiB") or the suffixes
  81 KB (=1000), MB (=1000*1000), and so on for GB, TB, PB, EB, ZB and YB.
  82 .TP
  83 .BR \-t , " \-\-streams " \fInumber
  84 Set the maximum number of compression streams that can be used for the device.
  85 The default is one stream.
  86 .TP
  87 .BR \-V , " \-\-version"
  88 Display version information and exit.
  89 .TP
  90 .BR \-h , " \-\-help"
  91 Display help text and exit.
  92
  93 .SH RETURN VALUE
  94 .B zramctl
  95 returns 0 on success, nonzero on failure.
  96
  97 .SH FILES
  98 .TP
  99 .I /dev/zram[0..N]
 100 zram block devices
 101
 102 .SH EXAMPLE
 103 The following commands set up a zram device with a size of one gigabyte
 104 and use it as swap device.
 105 .nf
 106 .IP
 107 # zramctl --find --size 1024M
 108 /dev/zram0
 109 # mkswap /dev/zram0
 110 # swapon /dev/zram0
 111  ...
 112 # swapoff /dev/zram0
 113 # zramctl --reset /dev/zram0
 114 .fi
 115 .SH SEE ALSO
 116 .UR http://git.\:kernel.\:org\:/cgit\:/linux\:/kernel\:/git\:/torvalds\:/linux.git\:/tree\:/Documentation\:/blockdev\:/zram.txt
 117 Linux kernel documentation
 118 .UE .
 119 .SH AUTHORS
 120 .nf
 121 Timofey Titovets <nefelim4ag@gmail.com>
 122 Karel Zak <kzak@redhat.com>
 123 .fi
 124 .SH AVAILABILITY
 125 The zramctl command is part of the util-linux package and is available from
 126 https://www.kernel.org/pub/linux/utils/util-linux/.