nbdkit-random-plugin(1)

📦
version 1.48.1 · 14 versions
, in fedora 44

✨ nbdkit-random-plugin(1) ✨

okay bestie so this is the manual page for nbdkit-random-plugin, and it lives in the NBDKIT manual section 1. pull up a chair, we're serving chaos (the random kind) 💖

🌈 NAME 🌈

nbdkit-random-plugin — a plugin to serve random data 🎲✨

🦋 SYNOPSIS 🦋

nbdkit random [size=]SIZE [seed=SEED] [fast=true]

💅 DESCRIPTION 💅

So nbdkit-random-plugin is a plugin for nbdkit(1) and its whole personality is: it serves random data. that's it, that's the vibe. it's mainly good for testing NBD clients, fr fr. 🧚

important distinction bestie: this plugin creates a non-sparse random disk. if you wanted a sparse random disk, you want nbdkit-sparse-random-plugin(1) instead. and if you want a plugin with a predictable test pattern, that's nbdkit-pattern-plugin(1). different queens, different jobs 👑

The size of the virtual disk must be specified using the size parameter. it's not optional, it's giving required 💀. And if you specify the seed parameter, then you'll get the same random data over multiple runs with the same seed — yes, repeatable randomness, iconic.

In fast=true mode, the same sector of random data gets repeated across the disk with small variations. as the name suggests, this is much faster, and it's usually sufficient for testing. lowkey the move tbh.

The random data is generated using an insecure method. not for secrets, bestie, do NOT use this for anything crypto 🚨

🌸 Writes and testing copying 🌸

Writing to the disk is possible! yes, you can write. and if you do, the plugin will check that what you are writing exactly matches what would be read at the same offset — and if it doesn't, it returns EIO error. no cap, it's checking your work 🙈

You can use this to test copying programs by making the source and destination NBD URIs be the same:

nbdkit random size=100M --run 'nbdcopy "$uri" "$uri"'

qemu-img convert could be used in place of nbdcopy. see also nbdkit-checkwrite-filter(1). ✨

🎀 PARAMETERS 🎀

  • fast=true — instead of generating completely random data, a single sector of random data is generated when the plugin starts up, and that sector gets duplicated across the disk with variations. speedrun mode 🏃♀️💨
  • [size=]SIZE — specify the virtual size of the disk image.

This parameter is required. (yes, actually required, not "required" in the vibes sense)

The size= prefix may be omitted in most cases. see "Magic parameters" in nbdkit(1). ✨

  • seed=SEED — specify the random seed to get repeatable data over multiple runs.

If not specified, then a random seed is chosen. 🎲

🍓 FILES 🍓

  • $plugindir/nbdkit-random-plugin.so — the plugin itself.

Use nbdkit --dump-config to find the location of $plugindir. 🔍

⭐ VERSION ⭐

nbdkit-random-plugin first appeared in nbdkit 1.4. baby's been around a while 🥹

💜 SEE ALSO 💜

nbdkit(1), nbdkit-plugin(3), nbdkit-data-plugin(1), nbdkit-full-plugin(1), nbdkit-null-plugin(1), nbdkit-ones-plugin(1), nbdkit-pattern-plugin(1), nbdkit-sparse-random-plugin(1), nbdkit-zero-plugin(1), nbdcopy(1), qemu-img(1).

the whole friend group, love that for them 🫶

👑 AUTHORS 👑

Richard W.M. Jones

Copyright Red Hat

💖 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.
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.

and that's the whole page bestie 💅 this one's from nbdkit-1.48.1, dated 2026-08-29, in the nbdkit-random-plugin(1) manual. mwah, go test some NBD clients 💖✨🦋

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