GLABEL(8)               FreeBSD System Manager's Manual              GLABEL(8)

NAME
     glabel - disk labelization control utility

SYNOPSIS
     glabel create [-v] name dev
     glabel destroy [-fv] name ...
     glabel label [-v] name dev
     glabel stop [-fv] name ...
     glabel clear [-v] dev ...
     glabel dump dev ...
     glabel refresh dev ...
     glabel list
     glabel status
     glabel load
     glabel unload

DESCRIPTION
     The glabel utility is used for GEOM provider labelization.  A label can
     be set up on a GEOM provider in two ways: "manual" or "automatic".  When
     using the "manual" method, no metadata are stored on the devices, so a
     label has to be configured by hand every time it is needed.  The
     "automatic" method uses on-disk metadata to store the label and detect it
     automatically in the future.

     This GEOM class also provides volume label detection for file systems.
     Those labels cannot be set with glabel, but must be set with the
     appropriate file system utility, e.g. for UFS the file system label is
     set with tunefs(8).  Currently supported file systems are:

           •   UFS1 volume names (directory /dev/ufs/).
           •   UFS2 volume names (directory /dev/ufs/).
           •   UFS1 file system IDs (directory /dev/ufsid/).
           •   UFS2 file system IDs (directory /dev/ufsid/).
           •   MSDOSFS (FAT12, FAT16, FAT32) (directory /dev/msdosfs/).
           •   CD ISO9660 (directory /dev/iso9660/).
           •   EXT2FS (directory /dev/ext2fs/).
           •   REISERFS (directory /dev/reiserfs/).
           •   NTFS (directory /dev/ntfs/).

     Support for partition metadata is implemented for:

           •   GPT labels (directory /dev/gpt/).
           •   GPT UUIDs (directory /dev/gptid/).

     Generic disk ID strings are exported as labels in the format
     /dev/diskid/GEOM_CLASS-ident e.g.  /dev/diskid/DISK-6QG3Z026.

     Generic labels created and managed solely by glabel(8) are created in the
     /dev/label/ directory.

     Note that for all label types, nested GEOM classes will cause additional
     device nodes to be created, with context-specific data appended to their
     names. E.g. for every node like /dev/label/bigdisk there will be
     additional entries for any partitions which the device contains, like
     /dev/label/bigdiskp1 and /dev/label/bigdiskp1a.

     The first argument to glabel indicates an action to be performed:

     create       Create temporary label name for the given provider.  This is
                  the "manual" method.  The kernel module geom_label.ko will
                  be loaded if it is not loaded already.

     label        Set up a label name for the given provider.  This is the
                  "automatic" method, where metadata is stored in a provider's
                  last sector.  The kernel module geom_label.ko will be loaded
                  if it is not loaded already.

     stop         Turn off the given label 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.

     refresh      Refresh / rediscover metadata from 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 labels.

     -v      Be more verbose.

SYSCTL VARIABLES
     The following sysctl(8) variables can be used to control the behavior of
     the LABEL GEOM class.  The default value is shown next to each variable.

     kern.geom.label.debug: 0
             Debug level of the LABEL GEOM class.  This can be set to a number
             between 0 and 2 inclusive.  If set to 0 minimal debug information
             is printed, and if set to 2 the maximum amount of debug
             information is printed.

     kern.geom.label.*.enable: 1
             Most LABEL providers implement a sysctl(8) flag and a tunable
             variable named in the above format. This flag controls if the
             label provider will be active, tasting devices and creating label
             nodes in the devfs(5) tree. It is sometimes desirable to disable
             certain label types if they conflict with other classes in
             complex GEOM topologies.

EXIT STATUS
     Exit status is 0 on success, and 1 if the command fails.

EXAMPLES
     The following example shows how to set up a label for disk "da2", create
     a file system on it, and mount it:

           glabel label -v usr /dev/da2
           newfs /dev/label/usr
           mount /dev/label/usr /usr
           [...]
           umount /usr
           glabel stop usr
           glabel unload

     The next example shows how to set up a label for a UFS file system:

           tunefs -L data /dev/da4s1a
           mount /dev/ufs/data /mnt/data

SEE ALSO
     geom(4), loader.conf(5), geom(8), mount(8), newfs(8), sysctl(8),
     tunefs(8), umount(8)

HISTORY
     The glabel utility appeared in FreeBSD 5.3.

AUTHORS
     Pawel Jakub Dawidek <pjd@FreeBSD.org>

FreeBSD 13.1-RELEASE-p6         March 12, 2017         FreeBSD 13.1-RELEASE-p6