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GCONCAT(8)                BSD System Manager's Manual               GCONCAT(8)

     gconcat -- disk concatenation control utility

     gconcat create [-v] name prov prov ...
     gconcat destroy [-fv] name ...
     gconcat label [-hv] name prov prov ...
     gconcat stop [-fv] name ...
     gconcat clear [-v] prov ...
     gconcat dump prov ...
     gconcat list
     gconcat status
     gconcat load
     gconcat unload

     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 auto-
     matically 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 num-
             ber between 0 and 3 inclusive.  If set to 0 minimal debug infor-
             mation 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

     geom(4), loader.conf(5), geom(8), mount(8), newfs(8), sysctl(8),
     umount(8), vinum(8)

     The gconcat utility appeared in FreeBSD 5.3.

     Pawel Jakub Dawidek <pjdATFreeBSD.org>

BSD                              May 21, 2004                              BSD