nbdkit-noextents-filter(1)

nbdkit-noextents-filter1

Disable extents in the underlying plugin

Usage

nbdkit --filter=noextents plugin

Overview

“Extents” are a feature of the NBD protocol / nbdkit which allow the client to detect sparse regions of the underlying disk. "nbdkit-noextents-filter" disables this so that the plugin appears to be fully allocated, at least to a client that requests structured replies. It is also possible to use the --no-meta-contexts or --no-sr options to nbdkit to prevent the client from negotiating extents at all, but that is accompanied by more side effects than this filter.

This filter can be useful when combined with nbdkit-file-plugin(1) serving a file from a file system known to have poor lseek(2) performance ("tmpfs" is known to be one such system).

Parameters

There are no parameters specific to nbdkit-noextents-filter. Any parameters are passed through to and processed by the underlying plugin in the normal way.

Files

$filterdir/nbdkit-noextents-filter.so

The filter.

Use "nbdkit --dump-config" to find the location of $filterdir.

Version

"nbdkit-noextents-filter" first appeared in nbdkit 1.14.

Releases

3 releases since Debian 11 (Bullseye); the text changed 2 times.

  1. 11
  2. 12
  3. 13

Authors

Richard W.M. Jones

License

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

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Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.

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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.

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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.

From nbdkit 1.42.3-1 in Debian 13 (Trixie). Parsed by carta from the page's man source.