1nbdkit-file-plugin(1) NBDKIT nbdkit-file-plugin(1)
2
6 nbdkit-file-plugin - nbdkit file plugin
7
9 nbdkit file [file=]FILENAME
10
12 "nbdkit-file-plugin" is a file serving plugin for nbdkit(1).
13 It serves the named "FILENAME" over NBD. Local block devices (eg.
15 /dev/sda) may also be served.
16 To concatenate multiple files, use nbdkit-split-plugin(1).
18 If you want to expose a file that resides on a file system known to
20 have poor lseek(2) performance when searching for holes ("tmpfs" is
21 known to be one such file system), you can use
22 nbdkit-noextents-filter(1) to avoid the penalty of probing for holes.
23
25 [file=]FILENAME
26 Serve the file named "FILENAME". A local block device name can
27 also be used here.
28 This parameter is required.
30 "file=" is a magic config key and may be omitted in most cases.
32 See "Magic parameters" in nbdkit(1).
33 rdelay
35 wdelay
36 These plugin parameters have been moved to the
37 nbdkit-delay-filter(1) filter. Modify the command line to add
38 --filter=delay in order to use these parameters.
39
41 You can obtain extra information about how the file plugin was compiled
42 by doing:
43 nbdkit file --dump-plugin
45 Some of the fields which may appear are listed below. Note these are
47 for information only and may be changed or removed at any time in the
48 future.
49 "file_blksszget=yes"
51 "file_blkzeroout=yes"
52 If both set, the plugin may be able to efficiently zero ranges of
53 block devices, where the driver and block device itself supports
54 this.
55 "file_falloc_fl_punch_hole=yes"
57 If set, the plugin may be able to punch holes (make sparse) files
58 and block devices.
59 "file_falloc_fl_zero_range=yes"
61 If set, the plugin may be able to efficiently zero ranges of files
62 and block devices.
63
65 -D file.zero=1
66 This enables very verbose debugging of the NBD zero request. This
67 can be used to tell if the file plugin is able to zero ranges in
68 the file or block device efficiently or not.
69
71 nbdkit(1), nbdkit-plugin(3), nbdkit-split-plugin(1),
72 nbdkit-partitioning-plugin(1), nbdkit-noextents-filter(1).
73
75 Eric Blake
76 Nir Soffer
78 Richard W.M. Jones
80
82 Copyright (C) 2013-2018 Red Hat Inc.
83
85 Redistribution and use in source and binary forms, with or without
86 modification, are permitted provided that the following conditions are
87 met:
88 · Redistributions of source code must retain the above copyright
90 notice, this list of conditions and the following disclaimer.
91 · Redistributions in binary form must reproduce the above copyright
93 notice, this list of conditions and the following disclaimer in the
94 documentation and/or other materials provided with the
95 distribution.
96 · Neither the name of Red Hat nor the names of its contributors may
98 be used to endorse or promote products derived from this software
99 without specific prior written permission.
100 THIS SOFTWARE IS PROVIDED BY RED HAT AND CONTRIBUTORS ''AS IS'' AND ANY
102 EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
103 IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
104 PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL RED HAT OR CONTRIBUTORS BE
105 LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
106 CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
107 SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
108 BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
109 WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
110 OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
111 ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
112nbdkit-1.12.3 2019-05-21 nbdkit-file-plugin(1)