1nbdkit-error-filter(1) NBDKIT nbdkit-error-filter(1)
2
6 nbdkit-error-filter - inject errors for testing clients
7
9 nbdkit --filter=error PLUGIN
10 [error=EPERM|EIO|ENOMEM|EINVAL|ENOSPC|ESHUTDOWN]
11 [error-rate=10%|0.1]
12 [error-file=/tmp/inject]
13 [error-pread=...] [error-pread-rate=...] [error-pread-file=...]
14 [error-pwrite=...] [error-pwrite-rate=...] [error-pwrite-file=...]
15 [error-trim=...] [error-trim-rate=...] [error-trim-file=...]
16 [error-zero=...] [error-zero-rate=...] [error-zero-file=...]
17 [error-extents=...] [error-extents-rate=...] [error-extents-file=...]
18
20 "nbdkit-error-filter" is an nbdkit filter that injects random errors
21 into replies from the server. This is used for testing that NBD
22 clients can handle errors.
23 All parameters are optional, but you should usually specify one of the
25 "error-rate" or "error-*-rate" parameters, otherwise this filter will
26 do nothing.
27
29 Inject a low rate of errors randomly into the connection:
30 nbdkit --filter=error file disk.img error-rate=1%
32 Reading, trimming and extents (block status) requests will be
34 successful, but all writes and zeroing will return "No space left on
35 device":
36 nbdkit --filter=error file disk.img \
38 error=ENOSPC \
39 error-pwrite-rate=100% \
40 error-zero-rate=100%
41 To make all connections fail hard 60 seconds after the server is
43 started, use:
44 rm -f /tmp/inject
46 nbdkit --filter=error file disk.img \
47 error-rate=100% \
48 error-file=/tmp/inject
49 sleep 60; touch /tmp/inject
50
52 error=EPERM|EIO|ENOMEM|EINVAL|ENOSPC|ESHUTDOWN
53 When a random error is injected, you can select which one from the
54 range of possible NBD errors (the NBD protocol only supports a
55 limited range of error codes).
56 This parameter is optional and the default is "EIO" ("Input/output
58 error").
59 error-rate=N%
61 error-rate=0..1
62 The rate of injected errors per NBD request. This can be expressed
63 as either a percentage between "0%" and "100%" or as a probability
64 between 0 and 1. If "0%" or 0 is used then no errors are ever
65 injected, and if "100%" or 1 is used then all requests return
66 errors.
67 This parameter is optional and the default is "0%". Unless you set
69 this, the filter will do nothing.
70 error-file=FILENAME
72 Errors will only be injected when FILENAME exists. (Note you must
73 also specify the "error-rate").
74 You can use this for fine-grained control over when to inject
76 errors, for example if you want to trigger an error at an exact
77 moment during a test, arrange for this file to be created at the
78 appropriate time. Or conversely to test error recovery in a
79 client, create the file initially, and then delete it to check the
80 client can recover.
81 This parameter is optional.
83 error-pread, error-pread-rate, error-pread-file.
85 Same as "error", "error-rate" and "error-file" but only apply the
86 settings to NBD pread requests.
87 error-pwrite, error-pwrite-rate, error-pwrite-file.
89 Same as "error", "error-rate" and "error-file" but only apply the
90 settings to NBD pwrite requests.
91 error-trim, error-trim-rate, error-trim-file.
93 Same as "error", "error-rate" and "error-file" but only apply the
94 settings to NBD trim requests.
95 error-zero, error-zero-rate, error-zero-file.
97 Same as "error", "error-rate" and "error-file" but only apply the
98 settings to NBD zero requests.
99 error-extents, error-extents-rate, error-extents-file.
101 Same as "error", "error-rate" and "error-file" but only apply the
102 settings to NBD block status requests to read extents.
103
105 Peculiar debug output
106 If you are looking at the debugging output (using "nbdkit -f -v") then
107 you may see peculiar "errors" appearing when using this filter, for
108 example:
109 nbdkit: file.9: debug: error: pread count=1024 offset=0 flags=0x0
111 In fact these are not errors, nbdkit core is simply printing the name
113 of the filter which happens to be "error". When this filter injects an
114 error you will see something like:
115 nbdkit: file.4: error: injecting ENOSPC error into pwrite
117
119 nbdkit(1), nbdkit-file-plugin(1), nbdkit-full-plugin(1),
120 nbdkit-filter(3).
121
123 Richard W.M. Jones
124
126 Copyright (C) 2018 Red Hat Inc.
127
129 Redistribution and use in source and binary forms, with or without
130 modification, are permitted provided that the following conditions are
131 met:
132 · Redistributions of source code must retain the above copyright
134 notice, this list of conditions and the following disclaimer.
135 · Redistributions in binary form must reproduce the above copyright
137 notice, this list of conditions and the following disclaimer in the
138 documentation and/or other materials provided with the
139 distribution.
140 · Neither the name of Red Hat nor the names of its contributors may
142 be used to endorse or promote products derived from this software
143 without specific prior written permission.
144 THIS SOFTWARE IS PROVIDED BY RED HAT AND CONTRIBUTORS ''AS IS'' AND ANY
146 EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
147 IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
148 PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL RED HAT OR CONTRIBUTORS BE
149 LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
150 CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
151 SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
152 BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
153 WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
154 OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
155 ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
156nbdkit-1.12.3 2019-05-21 nbdkit-error-filter(1)