1 .\" Copyright (c) 2004-2006 Pawel Jakub Dawidek <pjd@FreeBSD.org>
2 .\" All rights reserved.
4 .\" Redistribution and use in source and binary forms, with or without
5 .\" modification, are permitted provided that the following conditions
7 .\" 1. Redistributions of source code must retain the above copyright
8 .\" notice, this list of conditions and the following disclaimer.
9 .\" 2. Redistributions in binary form must reproduce the above copyright
10 .\" notice, this list of conditions and the following disclaimer in the
11 .\" documentation and/or other materials provided with the distribution.
13 .\" THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
14 .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
16 .\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
17 .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
18 .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
19 .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
20 .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
21 .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
22 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 .Nd "control utility for NOP GEOM class"
70 utility is used for setting up transparent providers on existing ones.
71 Its main purpose is testing other GEOM classes, as it allows forced provider
72 removal and I/O error simulation with a given probability.
73 It also gathers the following statistics: number of read requests, number of
74 write requests, number of bytes read and number of bytes written.
75 In addition, it can be used as a good starting point for implementing new GEOM
80 indicates an action to be performed:
81 .Bl -tag -width ".Cm configure"
83 Set up a transparent provider on the given devices.
84 If the operation succeeds, the new provider should appear with name
85 .Pa /dev/ Ns Ao Ar dev Ac Ns Pa .nop .
88 will be loaded if it is not loaded already.
90 Configure existing transparent provider.
91 At the moment it is only used for changing failure probability.
93 Turn off the given transparent providers.
95 Reset statistics for the given transparent providers.
111 .Bl -tag -width ".Fl r Ar rfailprob"
113 Specifies the error number to return on failure.
115 Force the removal of the specified provider.
117 Where to begin on the original provider.
118 .It Fl r Ar rfailprob
119 Specifies read failure probability in percent.
121 Size of the transparent provider.
123 Sector size of the transparent provider.
124 .It Fl w Ar wfailprob
125 Specifies write failure probability in percent.
132 variables can be used to control the behavior of the
135 The default value is shown next to each variable.
136 .Bl -tag -width indent
137 .It Va kern.geom.nop.debug : No 0
141 This can be set to a number between 0 and 2 inclusive.
142 If set to 0, minimal debug information is printed.
143 If set to 1, basic debug information is logged along with the I/O requests
144 that were returned as errors.
145 If set to 2, the maximum amount of debug information is printed including
149 Exit status is 0 on success, and 1 if the command fails.
151 The following example shows how to create a transparent provider for disk
153 with 50% write failure probability, and how to destroy it.
154 .Bd -literal -offset indent
155 gnop create -v -w 50 da0
156 gnop destroy -v da0.nop
159 The traffic statistics for the given transparent providers can be obtained
163 The example below shows the number of bytes written with
165 .Bd -literal -offset indent
179 .An Pawel Jakub Dawidek Aq pjd@FreeBSD.org