NAME
gconcat —
disk concatenation control
utility
SYNOPSIS
gconcat |
create [-v]
name prov ... |
gconcat |
destroy [-fv]
name ... |
gconcat |
label [-hv]
name prov ... |
gconcat |
stop [-fv]
name ... |
gconcat |
clear [-v]
prov ... |
gconcat |
dump prov ... |
gconcat |
list |
gconcat |
status |
gconcat |
load |
gconcat |
unload |
DESCRIPTION
Thegconcat 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.
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
CONCATGEOM 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
Exit status is 0 on success, and 1 if the command fails.
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
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
SEE ALSO
geom(4), loader.conf(5), geom(8), growfs(8), gvinum(8), mount(8), newfs(8), sysctl(8), umount(8)
HISTORY
The gconcat utility appeared in
FreeBSD 5.3.
AUTHORS
Pawel Jakub Dawidek <pjd@FreeBSD.org>