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GNOP(8)                 FreeBSD System Manager's Manual                GNOP(8)

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
     geom(4), geom(8)

HISTORY
     The gnop utility appeared in FreeBSD 5.3.

AUTHORS
     Pawel Jakub Dawidek <pjd@FreeBSD.org>

FreeBSD 11.0-PRERELEASE          May 21, 2004          FreeBSD 11.0-PRERELEASE

NAME | SYNOPSIS | DESCRIPTION | SYSCTL VARIABLES | EXAMPLES | DIAGNOSTICS | SEE ALSO | HISTORY | AUTHORS

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