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
  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 \-\-raw
  63 Use the raw format for status output.
  64 .TP
  65 .BR \-r , " \-\-reset"
  66 Reset the options of the specified zram device(s).  Zram device settings
  67 can be changed only after a reset.
  68 .TP
  69 .BR \-s , " \-\-size " \fIsize
  70 Create a zram device of the specified \fIsize\fR.
  71 Zram devices are aligned to memory pages; when the requested \fIsize\fR is
  72 not a multiple of the page size, it will be rounded up to the next multiple.
  73 When not otherwise specified, the unit of the \fIsize\fR parameter is bytes.
  74 .IP
  75 The \fIsize\fR argument may be followed by the multiplicative suffixes KiB (=1024),
  76 MiB (=1024*1024), and so on for GiB, TiB, PiB, EiB, ZiB and YiB (the "iB"
  77 is optional, e.g., "K" has the same meaning as "KiB") or the suffixes
  78 KB (=1000), MB (=1000*1000), and so on for GB, TB, PB, EB, ZB and YB.
  79 .TP
  80 .BR \-t , " \-\-streams " \fInumber
  81 Set the maximum number of compression streams that can be used for the device.
  82 The default is one stream.
  83 .TP
  84 .BR \-V , " \-\-version"
  85 Display version information and exit.
  86 .TP
  87 .BR \-h , " \-\-help"
  88 Display help text and exit.
  89
  90 .SH RETURN VALUE
  91 .B zramctl
  92 returns 0 on success, nonzero on failure.
  93
  94 .SH FILES
  95 .TP
  96 .I /dev/zram[0..N]
  97 zram block devices
  98
  99 .SH EXAMPLE
 100 The following commands set up a zram device with a size of one gigabyte
 101 and use it as swap device.
 102 .nf
 103 .IP
 104 # zramctl --find --size 1024M
 105 /dev/zram0
 106 # mkswap /dev/zram0
 107 # swapon /dev/zram0
 108  ...
 109 # swapoff /dev/zram0
 110 # zramctl --reset /dev/zram0
 111 .fi
 112 .SH SEE ALSO
 113 .UR http://git.\:kernel.\:org\:/cgit\:/linux\:/kernel\:/git\:/torvalds\:/linux.git\:/tree\:/Documentation\:/blockdev\:/zram.txt
 114 Linux kernel documentation
 115 .UE .
 116 .SH AUTHORS
 117 .nf
 118 Timofey Titovets <nefelim4ag@gmail.com>
 119 Karel Zak <kzak@redhat.com>
 120 .fi
 121 .SH AVAILABILITY
 122 The zramctl command is part of the util-linux package and is available from
 123 https://www.kernel.org/pub/linux/utils/util-linux/.