NAME
gconcat — disk concatenation control utility
SYNOPSIS
gconcat create
[−v] name prov prov
[prov [...]]
gconcat destroy [−fv] name
[name [...]]
gconcat label [−hv] name prov prov
[prov [...]]
gconcat stop [−fv] name
[name [...]]
gconcat clear [−v] prov
[prov [...]]
gconcat dump prov [prov [...]]
gconcat list [name [...]]
gconcat load [−v]
gconcat unload [−v]
DESCRIPTION
The gconcat utility is used for device concatenation configuration. The concatenation can be configured using two different methods: ’’manual’’ or ’’automatic’’. When using the ’’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 ’’automatic’’ method uses on-disk metadata to detect devices. Once devices are labeled, they will be automatically detected and configured.
The first argument to gconcat indicates an action to be performed:
create
Concatenate the given devices with specified name. This is the ’’manual’’ method. The kernel module geom_concat.ko will be loaded if it is not loaded already.
label
Concatenate the given devices with the specified name. This is the ’’automatic’’ method, where metadata are stored in every device’s last sector. The kernel module geom_concat.ko will be loaded if it is not loaded already.
stop
Turn off existing concatenate device by its name. This command does not touch on-disk metadata!
destroy
Same as stop.
clear
Clear metadata on the given devices.
dump
Dump metadata stored on the given devices.
list
List all or the given currently configured devices.
load
Load geom_concat.ko kernel module.
unload
Unload geom_concat.ko kernel module.
Additional options:
−f
Force the removal of the specified concatenated device.
−h
Hardcode providers’ names in metadata.
−v
Be more verbose.
SYSCTL VARIABLES
The following sysctl(8) variables can be used to control the behavior of the CONCAT GEOM class. The default value is shown next to each variable.
kern.geom.concat.debug: 0
Debug level of the 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.
EXAMPLES
The following example shows how to configure four disks for automatic concatenation, create a file system on it, and mount it:
gconcat label
-v data /dev/da0 /dev/da1 /dev/da2 /dev/da3
newfs /dev/concat/data
mount /dev/concat/data /mnt
[...]
umount /mnt
gconcat stop data
gconcat unload
DIAGNOSTICS
Exit status is 0 on success, and 1 if the command fails.
SEE ALSO
geom(4), loader.conf(5), geom(8), mount(8), newfs(8), sysctl(8), umount(8), vinum(8)
HISTORY
The gconcat utility appeared in FreeBSD 5.3.
AUTHORS
Pawel Jakub Dawidek <pjd [AT] FreeBSD.org>
BSD May 21, 2004 BSD