gconcat —
disk concatenation control utility
gconcat |
create [-v]
name prov ... |
gconcat |
destroy [-fv]
name ... |
gconcat |
label [-hv]
name prov ... |
gconcat |
stop [-fv]
name ... |
gconcat |
clear [-v]
prov ... |
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- See
geom(8).
status- See
geom(8).
load- See
geom(8).
unload- See
geom(8).
Additional options:
-f- Force the removal of the specified concatenated device.
-h- Hardcode providers' names in metadata.
-v- Be more verbose.
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 inclusive. If set to 0 minimal debug
information is printed, and if set to 3 the maximum amount of debug
information is printed.
Exit status is 0 on success, and 1 if the command fails.
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
Configure concatenated provider on one disk only. Create file
system. Add two more disks and extend existing file system.
gconcat label data /dev/da0
newfs /dev/concat/data
gconcat label data /dev/da0 /dev/da1 /dev/da2
growfs /dev/concat/data
The gconcat utility appeared in FreeBSD
5.3.
Visit the GSP FreeBSD Man Page Interface.