freebsd-skq/sbin/geom/class/concat/gconcat.8

.\" Copyright (c) 2004 Pawel Jakub Dawidek <pjd@FreeBSD.org>
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.\" $FreeBSD$
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.Dd May 21, 2004
.Dt GCONCAT 8
.Os
.Sh NAME
.Nm gconcat
.Nd "disk concatenation control utility"
.Sh SYNOPSIS
.Nm
.Cm create
.Op Fl v
.Ar name
.Ar dev1
.Ar dev2
.Op Ar dev3 Op Ar ...
.Nm
.Cm destroy
.Op Fl fv
.Ar name
.Op Ar name2 Op Ar ...
.Nm
.Cm label
.Op Fl v
.Ar name
.Ar dev1
.Ar dev2
.Op Ar dev3 Op Ar ...
.Nm
.Cm stop
.Op Fl fv
.Ar name
.Op Ar name2 Op Ar ...
.Nm
.Cm clear
.Op Fl v
.Ar dev1
.Op Ar dev2 Op Ar ...
.Nm
.Cm list
.Op Ar prov Op Ar ...
.Nm
.Cm load
.Op Fl v
.Nm
.Cm unload
.Op Fl v
.Sh DESCRIPTION
The
.Nm
utility is used for device concatenation configuration.
The concatenation can be configured using two different methods:
.Dq manual
or
.Dq automatic .
When using the
.Dq manual
method, no metadata are stored on the devices, so the concatenated
device has to be configured by hand every time it is needed.
The
.Dq automatic
method uses on-disk metadata to detect devices.
Once devices are labeled, they will be automatically detected and
configured.
.Pp
The first argument to
.Nm
indicates an action to be performed:
.Bl -tag -width ".Cm destroy"
.It Cm create
Concatenate the given devices with specified
.Ar name .
This is the
.Dq manual
method.
The kernel module
.Pa geom_concat.ko
will be loaded if it is not loaded already.
.It Cm label
Concatenate the given devices with the specified
.Ar name .
This is the
.Dq automatic
method, where metadata are stored in every device's last sector.
The kernel module
.Pa geom_concat.ko
will be loaded if it is not loaded already.
.It Cm stop
Turn off existing concatenate device by its
.Ar name .
This command does not touch on-disk metadata!
.It Cm destroy
Same as
.Cm stop .
.It Cm clear
Clear metadata on the given devices.
.It Cm list
List all or the given currently configured devices.
.It Cm load
Load
.Pa geom_concat.ko
kernel module.
.It Cm unload
Unload
.Pa geom_concat.ko
kernel module.
.El
.Pp
Additional options:
.Bl -tag -width indent
.It Fl f
Force the removal of the specified concatenated device.
.It Fl v
Be more verbose.
.El
.Sh SYSCTL VARIABLES
The following
.Xr sysctl 8
variables can be used to control the behavior of the
.Nm CONCAT
GEOM class.
The default value is shown next to each variable.
.Bl -tag -width indent
.It Va kern.geom.concat.debug : No 0
Debug level of the
.Nm CONCAT
GEOM class.
This can be set to a number between 0 and 3, both included.
If set to 0 minimal debug information is printed, and if set to 3 the
maximum amount of debug information in printed.
.El
.Sh EXAMPLES
The following example shows how to configure four disks for automatic
concatenation, create a file system on it, and mount it:
.Bd -literal -offset indent
gconcat label -v data /dev/da0 /dev/da1 /dev/da2 /dev/da3
newfs /dev/data.concat
mount /dev/data.concat /mnt
[...]
umount /mnt
gconcat stop data
gconcat unload
.Ed
.Sh DIAGNOSTICS
Exit status is 0 on success, and 1 if the command fails.
.Sh SEE ALSO
.Xr geom 4 ,
.Xr loader.conf 5 ,
.Xr geom 8 ,
.Xr mount 8 ,
.Xr newfs 8 ,
.Xr sysctl 8 ,
.Xr umount 8 ,
.Xr vinum 8
.Sh HISTORY
The
.Nm
utility appeared in
.Fx 5.3 .
.Sh AUTHORS
.An Pawel Jakub Dawidek Aq pjd@FreeBSD.org