Provided by: nbdkit_1.16.2-1ubuntu3_amd64 bug

NAME
       nbdkit-noextents-filter - disable extents in the underlying plugin


SYNOPSIS
        nbdkit --filter=noextents plugin


DESCRIPTION
       “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-sr
       option to nbdkit to prevent the client from using structured replies, which among its other side effects
       will prevent the client from querying extents at all.

       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.


SEE ALSO
       nbdkit(1), nbdkit-filter(3), nbdkit-fua-filter(1), nbdkit-nocache-filter(1), nbdkit-noparallel-filter(1),
       nbdkit-nozero-filter(1), nbdkit-file-plugin(1).


AUTHORS
       Richard W.M. Jones


COPYRIGHT
       Copyright (C) 2019 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.

       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.

nbdkit-1.16.2                                      2020-01-28                         nbdkit-noextents-filter(1)