xref: /freebsd/lib/geom/nop/gnop.8 (revision 0fca6ea1d4eea4c934cfff25ac9ee8ad6fe95583)
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25.Dd December 29, 2019
26.Dt GNOP 8
27.Os
28.Sh NAME
29.Nm gnop
30.Nd "control utility for NOP GEOM class"
31.Sh SYNOPSIS
32.Nm
33.Cm create
34.Op Fl v
35.Op Fl c Ar count_until_fail
36.Op Fl d Ar delaymsec
37.Op Fl e Ar error
38.Op Fl o Ar offset
39.Op Fl p Ar stripesize
40.Op Fl P Ar stripeoffset
41.Op Fl q Ar rdelayprob
42.Op Fl r Ar rfailprob
43.Op Fl s Ar size
44.Op Fl S Ar secsize
45.Op Fl w Ar wfailprob
46.Op Fl x Ar wdelayprob
47.Op Fl z Ar physpath
48.Op Fl Z Ar gnopname
49.Ar dev ...
50.Nm
51.Cm configure
52.Op Fl v
53.Op Fl c Ar count_until_fail
54.Op Fl d Ar delaymsec
55.Op Fl e Ar error
56.Op Fl q Ar rdelayprob
57.Op Fl r Ar rfailprob
58.Op Fl w Ar wfailprob
59.Op Fl x Ar wdelayprob
60.Ar prov ...
61.Nm
62.Cm destroy
63.Op Fl fv
64.Ar prov ...
65.Nm
66.Cm reset
67.Op Fl v
68.Ar prov ...
69.Nm
70.Cm list
71.Nm
72.Cm status
73.Nm
74.Cm load
75.Nm
76.Cm unload
77.Sh DESCRIPTION
78The
79.Nm
80utility is used for setting up transparent providers on existing ones.
81Its main purpose is testing other GEOM classes, as it allows forced provider
82removal and I/O error simulation with a given probability.
83It also gathers statistics on the number of read, write, delete,
84getattr, flush, and other requests, and the number of bytes read and written.
85.Nm
86can also be used as a good starting point for implementing new GEOM
87classes.
88.Pp
89The first argument to
90.Nm
91indicates an action to be performed:
92.Bl -tag -width ".Cm configure"
93.It Cm create
94Set up a transparent provider on the given devices.
95If the operation succeeds, the new provider should appear with name
96.Pa /dev/ Ns Ao Ar dev Ac Ns Pa .nop .
97The kernel module
98.Pa geom_nop.ko
99will be loaded if it is not loaded already.
100.It Cm configure
101Configure existing transparent provider.
102At the moment it is only used for changing failure probability.
103.It Cm destroy
104Turn off the given transparent providers.
105.It Cm reset
106Reset statistics for the given transparent providers.
107.It Cm list
108See
109.Xr geom 8 .
110.It Cm status
111See
112.Xr geom 8 .
113.It Cm load
114See
115.Xr geom 8 .
116.It Cm unload
117See
118.Xr geom 8 .
119.El
120.Pp
121Additional options:
122.Bl -tag -width "-c count_until_fail"
123.It Fl c Ar count_until_fail
124Specifies the number of I/O requests to allow before setting the read, write and
125delay failure probabilities.
126.It Fl d Ar delaymsec
127Specifies the delay of the requests in milliseconds.
128Note that requests will be delayed before they are sent to the backing device.
129.It Fl e Ar error
130Specifies the error number to return on failure.
131.It Fl f
132Force the removal of the specified provider.
133.It Fl o Ar offset
134Where to begin on the original provider.
135.It Fl p Ar stripesize
136Value of the stripesize property of the transparent provider.
137.It Fl P Ar stripeoffset
138Value of the stripeoffset property of the transparent provider.
139.It Fl q Ar rdelayprob
140Specifies read delay probability in percent.
141.It Fl r Ar rfailprob
142Specifies read failure probability in percent.
143.It Fl s Ar size
144Size of the transparent provider.
145.It Fl S Ar secsize
146Sector size of the transparent provider.
147.It Fl w Ar wfailprob
148Specifies write failure probability in percent.
149.It Fl v
150Be more verbose.
151.It Fl x Ar wdelayprob
152Specifies write delay probability in percent.
153.It Fl z Ar physpath
154Physical path of the transparent provider.
155.It Fl Z Ar gnopname
156The name of the new provider.
157The suffix
158.Dq .nop
159will be appended to the provider name.
160.El
161.Sh SYSCTL VARIABLES
162The following
163.Xr sysctl 8
164variables can be used to control the behavior of the
165.Nm NOP
166GEOM class.
167The default value is shown next to each variable.
168.Bl -tag -width indent
169.It Va kern.geom.nop.debug : No 0
170Debug level of the
171.Nm NOP
172GEOM class.
173This can be set to a number between 0 and 2 inclusive.
174If set to 0, minimal debug information is printed.
175If set to 1, basic debug information is logged along with the I/O requests
176that were returned as errors.
177If set to 2, the maximum amount of debug information is printed including
178all I/O requests.
179.El
180.Sh EXIT STATUS
181Exit status is 0 on success, and 1 if the command fails.
182.Sh EXAMPLES
183The following example shows how to create a transparent provider for disk
184.Pa /dev/da0
185with 50% write failure probability, and how to destroy it.
186.Bd -literal -offset indent
187gnop create -v -w 50 da0
188gnop destroy -v da0.nop
189.Ed
190.Pp
191The traffic statistics for the given transparent providers can be obtained
192with the
193.Cm list
194command.
195The example below shows the number of bytes written with
196.Xr newfs 8 :
197.Bd -literal -offset indent
198gnop create da0
199newfs /dev/da0.nop
200gnop list
201.Ed
202.Sh SEE ALSO
203.Xr geom 4 ,
204.Xr geom 8
205.Sh HISTORY
206The
207.Nm
208utility appeared in
209.Fx 5.3 .
210.Sh AUTHORS
211.An Pawel Jakub Dawidek Aq Mt pjd@FreeBSD.org
212