132 lines
3.4 KiB
Groff
132 lines
3.4 KiB
Groff
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.TH ZRAMCTL 8 "July 2014" "util-linux" "System Administration"
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.SH NAME
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zramctl \- set up and control zram devices
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.SH SYNOPSIS
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.ad l
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Get info:
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.sp
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.in +5
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.BR zramctl " [options]"
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.sp
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.in -5
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Reset zram:
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.sp
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.in +5
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.B "zramctl \-r"
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.IR zramdev ...
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.sp
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.in -5
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Print name of first unused zram device:
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.sp
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.in +5
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.B "zramctl \-f"
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.sp
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.in -5
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Set up a zram device:
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.sp
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.in +5
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.B zramctl
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.RB [ \-f " | "\fIzramdev\fP ]
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.RB [ \-s
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.IR size ]
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.RB [ \-t
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.IR number ]
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.RB [ \-a
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.IR algorithm ]
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.sp
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.in -5
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.ad b
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.SH DESCRIPTION
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.B zramctl
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is used to quickly set up zram device parameters, to reset zram devices, and to
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query the status of used zram devices.
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.PP
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If no option is given, all non-zero size zram devices are shown.
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.PP
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Note that \fIzramdev\fP node specified on command line has to already exist. The command
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.B zramctl
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creates a new /dev/zram<N> nodes only when \fB\-\-find\fR option specified. It's possible
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(and common) that after system boot /dev/zram<N> nodes are not created yet.
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.SH OPTIONS
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.TP
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.BR \-a , " \-\-algorithm lzo" | lz4 | lz4hc | deflate | 842
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Set the compression algorithm to be used for compressing data in the zram device.
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.TP
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.BR \-f , " \-\-find"
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Find the first unused zram device. If a \fB\-\-size\fR argument is present, then
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initialize the device.
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.TP
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.BR \-n , " \-\-noheadings"
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Do not print a header line in status output.
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.TP
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.BR \-o , " \-\-output " \fIlist
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Define the status output columns to be used. If no output arrangement is
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specified, then a default set is used.
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Use \fB\-\-help\fP to get a list of all supported columns.
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.TP
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.B \-\-output\-all
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Output all available columns.
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.TP
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.B \-\-raw
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Use the raw format for status output.
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.TP
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.BR \-r , " \-\-reset"
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Reset the options of the specified zram device(s). Zram device settings
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can be changed only after a reset.
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.TP
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.BR \-s , " \-\-size " \fIsize
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Create a zram device of the specified \fIsize\fR.
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Zram devices are aligned to memory pages; when the requested \fIsize\fR is
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not a multiple of the page size, it will be rounded up to the next multiple.
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When not otherwise specified, the unit of the \fIsize\fR parameter is bytes.
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.IP
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The \fIsize\fR argument may be followed by the multiplicative suffixes KiB (=1024),
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MiB (=1024*1024), and so on for GiB, TiB, PiB, EiB, ZiB and YiB (the "iB"
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is optional, e.g., "K" has the same meaning as "KiB") or the suffixes
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KB (=1000), MB (=1000*1000), and so on for GB, TB, PB, EB, ZB and YB.
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.TP
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.BR \-t , " \-\-streams " \fInumber
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Set the maximum number of compression streams that can be used for the device.
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The default is one stream.
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.TP
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.BR \-V , " \-\-version"
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Display version information and exit.
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.TP
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.BR \-h , " \-\-help"
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Display help text and exit.
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.SH RETURN VALUE
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.B zramctl
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returns 0 on success, nonzero on failure.
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.SH FILES
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.TP
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.I /dev/zram[0..N]
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zram block devices
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.SH EXAMPLE
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The following commands set up a zram device with a size of one gigabyte
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and use it as swap device.
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.nf
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.IP
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# zramctl --find --size 1024M
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/dev/zram0
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# mkswap /dev/zram0
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# swapon /dev/zram0
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...
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# swapoff /dev/zram0
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# zramctl --reset /dev/zram0
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.fi
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.SH SEE ALSO
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.UR http://git.\:kernel.\:org\:/cgit\:/linux\:/kernel\:/git\:/torvalds\:/linux.git\:/tree\:/Documentation\:/blockdev\:/zram.txt
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Linux kernel documentation
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.UE .
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.SH AUTHORS
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.nf
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Timofey Titovets <nefelim4ag@gmail.com>
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Karel Zak <kzak@redhat.com>
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.fi
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.SH AVAILABILITY
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The zramctl command is part of the util-linux package and is available from
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https://www.kernel.org/pub/linux/utils/util-linux/.
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