Provided by: nbdkit_1.24.1-2ubuntu4_amd64 
NAME
nbdkit-pattern-plugin - plugin to serve a fixed pattern of data for testing
SYNOPSIS
nbdkit pattern [size=]SIZE
DESCRIPTION
"nbdkit-pattern-plugin" is a plugin for nbdkit(1) which serves a fixed pattern of data,
read only. This is used for testing nbdkit filters and NBD clients. To create test disks
filled with other repeated patterns use nbdkit-data-plugin(1) instead.
The fixed pattern is the offset, as a 64 bit big endian integer, every 8 bytes. In
hexadecimal this looks like:
offset data
0000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 08
0010: 00 00 00 00 00 00 00 10 00 00 00 00 00 00 00 18
0020: 00 00 00 00 00 00 00 20 00 00 00 00 00 00 00 28
↗ └──────────┬──────────┘
byte at offset 0x28 │
│
64 bit big endian int
encoding offset 0x28
The size of the virtual disk must be specified using the "size" parameter. If the size is
not a multiple of 8 then the last 8 byte offset in the pattern is truncated.
Largest possible size
nbdkit itself limits plugins to 2⁶³-1 bytes (decimal: 9223372036854775807,
hexadecimal: 0x7fff_ffff_ffff_ffff).
To test if NBD clients are free of bugs (not to mention nbdkit itself) you can use:
nbdkit pattern 9223372036854775807
Note this is too large for qemu to open.
Little endian pattern
To get a little endian pattern instead of big endian apply nbdkit-swab-filter(1) on top of
this plugin:
nbdkit pattern 1G --filter=swab swab-bits=64
PARAMETERS
[size=]SIZE
Specify the virtual size of the disk image.
This parameter is required.
"size=" is a magic config key and may be omitted in most cases. See "Magic
parameters" in nbdkit(1).
FILES
$plugindir/nbdkit-pattern-plugin.so
The plugin.
Use "nbdkit --dump-config" to find the location of $plugindir.
VERSION
"nbdkit-pattern-plugin" first appeared in nbdkit 1.6.
SEE ALSO
nbdkit(1), nbdkit-plugin(3), nbdkit-data-plugin(1), nbdkit-full-plugin(1),
nbdkit-null-plugin(1), nbdkit-offset-filter(1), nbdkit-random-plugin(1),
nbdkit-sparse-random-plugin(1), nbdkit-swab-filter(1), nbdkit-zero-plugin(1).
AUTHORS
Richard W.M. Jones
COPYRIGHT
Copyright (C) 2018 Red Hat Inc.
LICENSE
Redistribution and use in source and binary forms, with or without modification, are
permitted provided that the following conditions are met:
• Redistributions of source code must retain the above copyright notice, this list of
conditions and the following disclaimer.
• Redistributions in binary form must reproduce the above copyright notice, this list of
conditions and the following disclaimer in the documentation and/or other materials
provided with the distribution.
• Neither the name of Red Hat nor the names of its contributors may be used to endorse
or promote products derived from this software without specific prior written
permission.
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