1 .TH ZRAMCTL 8 "July 2014" "util-linux" "System Administration"
3 zramctl \- set up and control zram devices
9 .BR zramctl " [options]"
19 Print name of first unused zram device:
29 .RB [ \-f " | "\fIzramdev\fP ]
41 is used to quickly set up zram device parameters, to reset zram devices, and to
42 query the status of used zram devices.
44 If no option is given, all non-zero size zram devices are shown.
47 .BR \-a , " \-\-algorithm lzo" | lz4 | lz4hc | deflate | 842
48 Set the compression algorithm to be used for compressing data in the zram device.
51 Find the first unused zram device. If a \fB--size\fR argument is present, then
52 initialize the device.
54 .BR \-n , " \-\-noheadings"
55 Do not print a header line in status output.
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.
63 Output all available columns.
66 Use the raw format for status output.
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.
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.
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.
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.
87 .BR \-V , " \-\-version"
88 Display version information and exit.
91 Display help text and exit.
95 returns 0 on success, nonzero on failure.
103 The following commands set up a zram device with a size of one gigabyte
104 and use it as swap device.
107 # zramctl --find --size 1024M
113 # zramctl --reset /dev/zram0
116 .UR http://git.\:kernel.\:org\:/cgit\:/linux\:/kernel\:/git\:/torvalds\:/linux.git\:/tree\:/Documentation\:/blockdev\:/zram.txt
117 Linux kernel documentation
121 Timofey Titovets <nefelim4ag@gmail.com>
122 Karel Zak <kzak@redhat.com>
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/.