1nbdkit-noextents-filter(1)          NBDKIT          nbdkit-noextents-filter(1)
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NAME

6       nbdkit-noextents-filter - disable extents in the underlying plugin
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SYNOPSIS

9        nbdkit --filter=noextents plugin
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DESCRIPTION

12       “Extents” are a feature of the NBD protocol / nbdkit which allow the
13       client to detect sparse regions of the underlying disk.
14       "nbdkit-noextents-filter" disables this so that the plugin appears to
15       be fully allocated, at least to a client that requests structured
16       replies.  It is also possible to use the --no-sr option to nbdkit to
17       prevent the client from using structured replies, which among its other
18       side effects will prevent the client from querying extents at all.
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20       This filter can be useful when combined with nbdkit-file-plugin(1)
21       serving a file from a file system known to have poor lseek(2)
22       performance ("tmpfs" is known to be one such system).
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PARAMETERS

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

30       $filterdir/nbdkit-noextents-filter.so
31           The filter.
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33           Use "nbdkit --dump-config" to find the location of $filterdir.
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VERSION

36       "nbdkit-noextents-filter" first appeared in nbdkit 1.14.
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SEE ALSO

39       nbdkit(1), nbdkit-filter(3), nbdkit-extentlist-filter(1),
40       nbdkit-fua-filter(1), nbdkit-nocache-filter(1),
41       nbdkit-noparallel-filter(1), nbdkit-nozero-filter(1),
42       nbdkit-file-plugin(1).
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AUTHORS

45       Richard W.M. Jones
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48       Copyright (C) 2019 Red Hat Inc.
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LICENSE

51       Redistribution and use in source and binary forms, with or without
52       modification, are permitted provided that the following conditions are
53       met:
54
55       ·   Redistributions of source code must retain the above copyright
56           notice, this list of conditions and the following disclaimer.
57
58       ·   Redistributions in binary form must reproduce the above copyright
59           notice, this list of conditions and the following disclaimer in the
60           documentation and/or other materials provided with the
61           distribution.
62
63       ·   Neither the name of Red Hat nor the names of its contributors may
64           be used to endorse or promote products derived from this software
65           without specific prior written permission.
66
67       THIS SOFTWARE IS PROVIDED BY RED HAT AND CONTRIBUTORS ''AS IS'' AND ANY
68       EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
69       IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
70       PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL RED HAT OR CONTRIBUTORS BE
71       LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
72       CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
73       SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
74       BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
75       WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
76       OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
77       ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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81nbdkit-1.18.4                     2020-04-16        nbdkit-noextents-filter(1)
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