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

     glabel -- disk labelization control utility

     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

     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 appro-
     priate file system	utility, e.g. for UFS the file system label is set
     with tunefs(8).  Currently	supported file systems are:

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

     Support for partition metadata is implemented for:

	   o   GPT labels (directory /dev/gpt/).
	   o   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 addi-
     tional 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.

     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 informa-
	     tion 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 la-
	     bel 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	com-
	     plex GEOM topologies.

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

     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

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

     The glabel	utility	appeared in FreeBSD 5.3.

     Pawel Jakub Dawidek <>

FreeBSD	13.0			March 12, 2017			  FreeBSD 13.0


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