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nbdkit-noparallel-filter(1)	    NBDKIT	   nbdkit-noparallel-filter(1)

NAME
       nbdkit-noparallel-filter	- nbdkit noparallel filter

SYNOPSIS
	nbdkit --filter=noparallel plugin [serialize=MODE] [plugin-args...]

DESCRIPTION
       "nbdkit-noparallel-filter" is a filter that intentionally disables
       parallelism in handling requests	from clients. It is mainly useful for
       evaluating timing differences between various levels of parallelism.
       It can also be used as a	way to work around any bugs in a plugin's
       claimed level of	parallel support, without recompiling the plugin, or
       to ease efforts when connecting with a client that can batch up several
       requests	but is not prepared to handle out-of-order replies.

       To limit	the number of concurrent clients it's usually better to	use
       nbdkit-limit-filter(1).

PARAMETERS
       serialize=requests
       serialize=all-requests
       serialize=connections
	   Optional, controls how much serialization the filter	will enforce.
	   Mode	requests (default) prevents a single client from having	more
	   than	one in-flight request, but does	not prevent parallel requests
	   from	a second connection (if	the plugin supports that). Mode	all-
	   requests is stricter, enforcing that	at most	one request
	   (regardless of connection) will be active, but does not prevent
	   parallel connections	(if the	plugin supports	that). Mode
	   connections is strictest, where there can be	at most	one client at
	   a time, and where the server	will no	longer advertise
	   "NBD_FLAG_MULTI_CONN" to clients.

EXAMPLES
       Serve the file disk.img,	but disallow out-of-order transaction
       completion to a given client:

	nbdkit --filter=noparallel file	disk.img

       Serve the file disk.img,	but allowing only one client at	a time:

	nbdkit --filter=noparallel file	serialize=connections disk.img

FILES
       $filterdir/nbdkit-noparallel-filter.so
	   The filter.

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

VERSION
       "nbdkit-noparallel-filter" first	appeared in nbdkit 1.14.

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

AUTHORS
       Eric Blake

COPYRIGHT
       Copyright (C) 2018-2020 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:

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

       o   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.

       o   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-1.20.4			  2021-03-01	   nbdkit-noparallel-filter(1)

NAME | SYNOPSIS | DESCRIPTION | PARAMETERS | EXAMPLES | FILES | VERSION | SEE ALSO | AUTHORS | COPYRIGHT | LICENSE

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