.\" -*- mode: troff; coding: utf-8 -*- .\" Automatically generated by Podwrapper::Man 1.38.2 (Pod::Simple 3.43) .\" .\" Standard preamble: .\" ======================================================================== .de Sp \" Vertical space (when we can't use .PP) .if t .sp .5v .if n .sp .. .de Vb \" Begin verbatim text .ft CW .nf .ne \\$1 .. .de Ve \" End verbatim text .ft R .fi .. .\" \*(C` and \*(C' are quotes in nroff, nothing in troff, for use with C<>. .ie n \{\ . ds C` "" . ds C' "" 'br\} .el\{\ . ds C` . ds C' 'br\} .\" .\" Escape single quotes in literal strings from groff's Unicode transform. .ie \n(.g .ds Aq \(aq .el .ds Aq ' .\" .\" If the F register is >0, we'll generate index entries on stderr for .\" titles (.TH), headers (.SH), subsections (.SS), items (.Ip), and index .\" entries marked with X<> in POD. Of course, you'll have to process the .\" output yourself in some meaningful fashion. .\" .\" Avoid warning from groff about undefined register 'F'. .de IX .. .nr rF 0 .if \n(.g .if rF .nr rF 1 .if (\n(rF:(\n(.g==0)) \{\ . if \nF \{\ . de IX . tm Index:\\$1\t\\n%\t"\\$2" .. . if !\nF==2 \{\ . nr % 0 . nr F 2 . \} . \} .\} .rr rF .\" ======================================================================== .\" .IX Title "nbdkit-pattern-plugin 1" .TH nbdkit-pattern-plugin 1 2024-05-10 nbdkit-1.38.2 NBDKIT .\" For nroff, turn off justification. Always turn off hyphenation; it makes .\" way too many mistakes in technical documents. .if n .ad l .nh .SH NAME nbdkit\-pattern\-plugin \- plugin to serve a fixed pattern of data for testing .SH SYNOPSIS .IX Header "SYNOPSIS" .Vb 1 \& nbdkit pattern [size=]SIZE .Ve .SH DESCRIPTION .IX Header "DESCRIPTION" \&\f(CW\*(C`nbdkit\-pattern\-plugin\*(C'\fR is a plugin for \fBnbdkit\fR\|(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 \fBnbdkit\-data\-plugin\fR\|(1) or \&\fBnbdkit\-ones\-plugin\fR\|(1) instead. .PP The fixed pattern is the offset, as a 64 bit big endian integer, every 8 bytes. In hexadecimal this looks like: .PP .Vb 9 \& 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 .Ve .PP The size of the virtual disk must be specified using the \f(CW\*(C`size\*(C'\fR parameter. If the size is not a multiple of 8 then the last 8 byte offset in the pattern is truncated. .SS "Largest possible size" .IX Subsection "Largest possible size" nbdkit itself limits plugins to 2⁶³\-1 bytes (decimal:\ 9223372036854775807, hexadecimal:\ 0x7fff_ffff_ffff_ffff). .PP To test if NBD clients are free of bugs (not to mention nbdkit itself) you can use: .PP .Vb 1 \& nbdkit pattern 9223372036854775807 .Ve .PP Note this is too large for qemu to open. .SS "Little endian pattern" .IX Subsection "Little endian pattern" To get a little endian pattern instead of big endian apply \&\fBnbdkit\-swab\-filter\fR\|(1) on top of this plugin: .PP .Vb 1 \& nbdkit pattern 1G \-\-filter=swab swab\-bits=64 .Ve .SH PARAMETERS .IX Header "PARAMETERS" .IP [\fBsize=\fR]SIZE 4 .IX Item "[size=]SIZE" Specify the virtual size of the disk image. .Sp This parameter is required. .Sp \&\f(CW\*(C`size=\*(C'\fR is a magic config key and may be omitted in most cases. See "Magic parameters" in \fBnbdkit\fR\|(1). .SH FILES .IX Header "FILES" .ie n .IP \fR\fI$plugindir\fR\fI/nbdkit\-pattern\-plugin.so\fR 4 .el .IP \fR\f(CI$plugindir\fR\fI/nbdkit\-pattern\-plugin.so\fR 4 .IX Item "$plugindir/nbdkit-pattern-plugin.so" The plugin. .Sp Use \f(CW\*(C`nbdkit \-\-dump\-config\*(C'\fR to find the location of \f(CW$plugindir\fR. .SH VERSION .IX Header "VERSION" \&\f(CW\*(C`nbdkit\-pattern\-plugin\*(C'\fR first appeared in nbdkit 1.6. .SH "SEE ALSO" .IX Header "SEE ALSO" \&\fBnbdkit\fR\|(1), \&\fBnbdkit\-plugin\fR\|(3), \&\fBnbdkit\-data\-plugin\fR\|(1), \&\fBnbdkit\-full\-plugin\fR\|(1), \&\fBnbdkit\-null\-plugin\fR\|(1), \&\fBnbdkit\-ones\-plugin\fR\|(1), \&\fBnbdkit\-offset\-filter\fR\|(1), \&\fBnbdkit\-random\-plugin\fR\|(1), \&\fBnbdkit\-sparse\-random\-plugin\fR\|(1), \&\fBnbdkit\-swab\-filter\fR\|(1), \&\fBnbdkit\-zero\-plugin\fR\|(1). .SH AUTHORS .IX Header "AUTHORS" Richard W.M. Jones .SH COPYRIGHT .IX Header "COPYRIGHT" Copyright Red Hat .SH LICENSE .IX Header "LICENSE" Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: .IP \(bu 4 Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. .IP \(bu 4 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. .IP \(bu 4 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. .PP THIS SOFTWARE IS PROVIDED BY RED HAT AND CONTRIBUTORS ''AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL RED HAT OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.