1.\" Copyright (c) 2015 The DragonFly BSD Project. 2.\" All rights reserved. 3.\" 4.\" This code is derived from software contributed to The DragonFly BSD Project 5.\" by Tomohiro Kusumi <tkusumi@netbsd.org> 6.\" 7.\" Redistribution and use in source and binary forms, with or without 8.\" modification, are permitted provided that the following conditions 9.\" are met: 10.\" 1. Redistributions of source code must retain the above copyright 11.\" notice, this list of conditions and the following disclaimer. 12.\" 2. Redistributions in binary form must reproduce the above copyright 13.\" notice, this list of conditions and the following disclaimer in the 14.\" documentation and/or other materials provided with the distribution. 15.\" 16.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 17.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 18.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 19.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 20.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 21.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 22.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 23.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 24.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 25.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 26.\" POSSIBILITY OF SUCH DAMAGE. 27.Dd November 17, 2015 28.Dt DM_TARGET_FLAKEY 4 29.Os 30.Sh NAME 31.Nm dm_target_flakey 32.Nd Device-mapper flakey target 33.Sh SYNOPSIS 34To compile this driver into the kernel, 35place the following lines in your 36kernel configuration file: 37.Bd -ragged -offset indent 38.Cd "device dm" 39.Cd "device dm_target_flakey" 40.Ed 41.Pp 42Alternatively, to load the driver as a 43module at boot time, place the following line in 44.Xr loader.conf 5 : 45.Bd -literal -offset indent 46dm_target_flakey_load="YES" 47.Ed 48.Sh DESCRIPTION 49The 50.Nm 51target for 52.Xr dm 4 53provides periodic unreliable I/O behavior to simulate failing devices for testing purposes. 54.Dq Nm dmsetup Cm create 55takes the following list of parameters for the 56.Nm 57table. 58.Bd -ragged -offset indent 59.Cd "<device_path> <offset> <up_interval> <down_interval> [<num_feature_parameters> [<feature_parameters>]]" 60.Ed 61.Pp 62The first four parameters are mandatory. 63.Nm 64is similar to 65.Xr dm_target_linear 4 66except that 67.Nm 68has parameters for periodic unreliable I/O behavior. 69.Pp 70<device_path> is a path to the underlying device. 71<offset> is the starting sector within the device. 72<up_interval> is the number of seconds device is available. 73<down_interval> is the number of seconds device returns errors. 74The device has periodic unreliable I/O behavior for <down_interval> 75seconds every other <up_interval> seconds starting from the time 76the table is loaded by 77.Xr dmsetup 8 . 78.Pp 79Optional <feature_parameters> are as follows. 80<num_feature_parameters> takes the number of parameters for <feature_parameters>. 81In other words <num_feature_parameters> is the number of parameters after this. 82If <feature_parameters> are not specified, all I/Os return error during <down_interval>. 83.Pp 84.Dq Nm drop_writes 85feature takes no additional parameters. 86All write I/Os are silently ignored. 87.Bd -ragged -offset indent 88.Cd "[drop_writes]" 89.Ed 90.Pp 91.Dq Nm corrupt_bio_byte 92feature takes four additional mandatory parameters. 93It replaces <Nth_byte> of the 94.Dq Nm struct Cm buf 95data 96whose direction is <direction> with <value> during <down_interval>. 97.Bd -ragged -offset indent 98.Cd "[corrupt_bio_byte <Nth_byte> <direction> <value> <flags>]" 99.Ed 100.Pp 101<Nth_byte> is the offset of the 102.Dq Nm struct Cm buf 103data to replace. Counting starts at 1 to replace the first byte of the data. 104<direction> is either 'r' for reads or 'w' for writes. Using 'w' is imcompatible with 105.Dq Nm drop_writes 106feature. 107<value> is the value to replace which must be between 0 and 255. 108<flags> makes 109.Nm 110perform the replacement only if 111.Dq Nm b_flags 112field of 113.Dq Nm struct Cm buf 114has all the specified flags set. 115.Sh SEE ALSO 116.Xr dm 4 , 117.Xr dmsetup 8 118.Sh HISTORY 119The 120.Nm 121.Xr dm 4 122target first appeared in 123.Dx 4.3 . 124.Sh AUTHORS 125.An Tomohiro Kusumi Aq Mt tkusumi@netbsd.org 126