NAME
gnop — control utility for NOP GEOM class
SYNOPSIS
gnop create
[−v] [−f failprob]
[−o offset]
[−s size]
[−S secsize] dev1
[dev2 [...]]
gnop configure [−v]
[−f failprob] prov1
[prov2 [...]]
gnop destroy [−fv] prov1
[prov2 [...]]
gnop list [prov [...]]
gnop load [−v]
gnop unload [−v]
DESCRIPTION
The gnop utility is used for setting up transparent providers on existing ones. Its main purpose is testing other GEOM classes, as it allows force providers removal and I/O errors simulation with a given probability. It is also a good starting point for implementing new GEOM classes.
The first argument to gnop indicates an action to be performed:
create
Set up a transparent provider on the given devices. If operation succeded, new provider should appear with name /dev/⟨
dev ⟩ .nop. The kernel module geom_nop.ko will be loaded if it is not loaded already.
configure
Configure existing transparent provider. At the moment it is only used for changing failure probability. The kernel module geom_nop.ko will be loaded if it is not loaded already.
destroy
Turn off the given transparent providers.
list
List all or the given currently configured providers.
load
Load geom_nop.ko kernel module.
unload
Unload geom_nop.ko kernel module.
Additional options:
−f
Force the removal of the specified provider.
−f failprob
Specifies failure probability in percentage.
−o offset
Where to begin on the original provider.
−s size
Size of the transparent provider.
−S secsize
Sector size of the transparent provider.
−v
Be more verbose.
SYSCTL VARIABLES
The following sysctl(8) variables can be used to control the behavior of the NOP GEOM class. The default value is shown next to each variable.
kern.geom.nop.debug: 0
Debug level of the NOP GEOM class. This can be set to a number between 0 and 2, both included. If set to 0 minimal debug information is printed, and if set to 2 the maximum amount of debug information in printed.
EXAMPLES
The following example shows how to create a transparent provider for disk /dev/da0 with 50% failure probability and destroy it.
gnop create -v
-f 50 da0
gnop destroy -v da0.nop
DIAGNOSTICS
Exit status is 0 on success, and 1 if the command fails.
SEE ALSO
HISTORY
The gnop utility appeared in FreeBSD 5.3.
AUTHORS
Pawel Jakub Dawidek <pjd [AT] FreeBSD.org>
BSD May 21, 2004 BSD