3 nbdkit-file-plugin - nbdkit file plugin
7 nbdkit file [file=]FILENAME
11 C<nbdkit-file-plugin> is a file serving plugin for L<nbdkit(1)>.
13 It serves the named C<FILENAME> over NBD. Local block devices
14 (eg. F</dev/sda>) may also be served.
16 To concatenate multiple files, use L<nbdkit-split-plugin(1)>.
18 If you want to expose a file that resides on a file system known to
19 have poor C<lseek(2)> performance when searching for holes (C<tmpfs>
20 is known to be one such file system), you can use
21 L<nbdkit-noextents-filter(1)> to avoid the penalty of probing for
28 =item [B<file=>]FILENAME
30 Serve the file named C<FILENAME>. A local block device name can also
33 This parameter is required.
35 C<file=> is a magic config key and may be omitted in most cases.
36 See L<nbdkit(1)/Magic parameters>.
42 These plugin parameters have been moved to the
43 L<nbdkit-delay-filter(1)> filter. Modify the command line to add
44 I<--filter=delay> in order to use these parameters.
48 =head1 DUMP-PLUGIN OUTPUT
50 You can obtain extra information about how the file plugin was
53 nbdkit file --dump-plugin
55 Some of the fields which may appear are listed below. Note these are
56 for information only and may be changed or removed at any time in the
61 =item C<file_blksszget=yes>
63 =item C<file_blkzeroout=yes>
65 If both set, the plugin may be able to efficiently zero ranges of
66 block devices, where the driver and block device itself supports this.
68 =item C<file_falloc_fl_punch_hole=yes>
70 If set, the plugin may be able to punch holes (make sparse) files and
73 =item C<file_falloc_fl_zero_range=yes>
75 If set, the plugin may be able to efficiently zero ranges of files and
84 =item B<-D file.zero=1>
86 This enables very verbose debugging of the NBD zero request. This can
87 be used to tell if the file plugin is able to zero ranges in the file
88 or block device efficiently or not.
96 =item F<$plugindir/nbdkit-file-plugin.so>
100 Use C<nbdkit --dump-config> to find the location of C<$plugindir>.
106 C<nbdkit-file-plugin> first appeared in nbdkit 1.0.
112 L<nbdkit-split-plugin(1)>,
113 L<nbdkit-partitioning-plugin(1)>,
114 L<nbdkit-noextents-filter(1)>.
126 Copyright (C) 2013-2018 Red Hat Inc.