NAME

       nbdkit-file-plugin - nbdkit file plugin

SYNOPSIS

        nbdkit file [file=]FILENAME

DESCRIPTION

       "nbdkit-file-plugin" is a file serving plugin for nbdkit(1).

       It serves the named "FILENAME" over NBD.  Local block devices (eg. /dev/sda) may also be served.

       To concatenate multiple files, use nbdkit-split-plugin(1).

       If you want to expose a file that resides on a file system known to have poor lseek(2) performance when
       searching for holes ("tmpfs" is known to be one such file system), you can use nbdkit-noextents-filter(1)
       to avoid the penalty of probing for holes.

PARAMETERS

       [file=]FILENAME
           Serve the file named "FILENAME".  A local block device name can also be used here.

           This parameter is required.

           "file=" is a magic config key and may be omitted in most cases.  See "Magic parameters" in nbdkit(1).

       rdelay
       wdelay
           These  plugin  parameters  have  been moved to the nbdkit-delay-filter(1) filter.  Modify the command
           line to add --filter=delay in order to use these parameters.

DUMP-PLUGIN OUTPUT

       You can obtain extra information about how the file plugin was compiled by doing:

        nbdkit file --dump-plugin

       Some of the fields which may appear are listed below.  Note these are for information  only  and  may  be
       changed or removed at any time in the future.

       "file_blksszget=yes"
       "file_blkzeroout=yes"
           If both set, the plugin may be able to efficiently zero ranges of block devices, where the driver and
           block device itself supports this.

       "file_falloc_fl_punch_hole=yes"
           If set, the plugin may be able to punch holes (make sparse) files and block devices.

       "file_falloc_fl_zero_range=yes"
           If set, the plugin may be able to efficiently zero ranges of files and block devices.

DEBUG FLAG

       -D file.zero=1
           This  enables  very  verbose debugging of the NBD zero request.  This can be used to tell if the file
           plugin is able to zero ranges in the file or block device efficiently or not.

FILES

       $plugindir/nbdkit-file-plugin.so
           The plugin.

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

VERSION

       "nbdkit-file-plugin" first appeared in nbdkit 1.0.

SEE ALSO

       nbdkit(1),        nbdkit-plugin(3),        nbdkit-split-plugin(1),         nbdkit-partitioning-plugin(1),
       nbdkit-noextents-filter(1).

AUTHORS

       Eric Blake

       Nir Soffer

       Richard W.M. Jones

COPYRIGHT

       Copyright (C) 2013-2018 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.

       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-file-plugin(1)