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disklabel(8)							 disklabel(8)



NAME

  disklabel - Reads and	writes a disk pack label and formats disk partitions

SYNOPSIS

  /sbin/disklabel [-r] [disk]

  /sbin/disklabel [-r] -f  filename

  /sbin/disklabel -w  disk [type[packid]]

  /sbin/disklabel -wr  [-n] [-t	{ufs | advfs}] [disk] [type [packid] [xxboot
  bootxx]]

  /sbin/disklabel -wr  [-n] [-t	{ufs | advfs | cdfs}] -ffilename [packid]
  [xxboot bootxx]

  /sbin/disklabel -e  [-r] disk

  /sbin/disklabel -e  -f  filename

  /sbin/disklabel -R  [-t {ufs | advfs}] disk  protofile

  /sbin/disklabel -Rr  [-t  {ufs | advfs}] disk	 protofile { type   |
  xxboot  bootxx }

  /sbin/disklabel [-N  | -W] disk

  /sbin/disklabel -z  disk

  /sbin/disklabel -s  -F  disk fstype

  /sbin/disklabel -p  disk [type]

OPTIONS

  -e  Edits an existing	label.

  -f filename
      Specifies	the type of image file for operations.	The default image
      file type	is cdfs, to indicate that the image file was created in	ISO
      9660 Rock	Ridge format.  The cdfs	default	applies	only when the -f
      option is	used.

  -F  Enables you to force an override of the current file system type.	You
      can set the file system type by using the	-s option. If the target disk
      partition	is in use, the disklabel command displays a warning message
      and does not set a file system type. This	safety feature prevents	you
      from accidentally	overwriting any	partition that is in use. If you are
      certain that you want to set a new file system type, you can choose to
      ignore the warning and specify the -F option to override the safety
      feature.

  -n  Writes an	initial	label to a disk	which is then labeled, but not boot-
      able. Use	the -wr	option alone to	create a bootable disk.

  -N  Disallows	writing	of the pack label area on the specified	disk. (See
      the -W option.)

  -p  Prints label operands for	the specified disk to stdout.

  -r  Reads or writes the label	directly to or from the	disk, rather than
      operating	on the in-memory copy of the label.  Used with the -w option,
      this option creates a bootable disk.

  -R  Restores a disk label that was formatted in a prior operation and	saved
      in an ASCII file.

  -s  Sets the file system type	(fstype) field in the disk label. See the -F
      option, which enables you	to force an override of	any existing set-
      tings.

  -t ufs|advfs|cdfs
      Specifies	which type of the local	file system the	boot blocks describe,
      UFS, AdvFS, or CDFS.

  -w  Writes a standard	label on the designated	drive. Used with the -r
      option, this option creates a bootable disk.

  -W  Allows writing of	the pack label area on the specified disk. (See	-N.)

  -z  Zeros (clears) the disk label.

PARAMETERS

  disk
      Identifies the disk on which you want to perform a labelling operation.
      You use the disk's device	special	file name, such	as dsk0	or
      /dev/rdisk/dsk0a.	 If you	do not specify the disk	partition, the disk-
      label command uses the first partition that has a	zero offset. Typi-
      cally, this is the a or c	partition. If the full path name is used, it
      must be a	character special device name and not the block	device name.

  filename
      Specifies	an image file name that	the disklabel command reads to per-
      form the specified operation.

  type
      Specifies	the type (or model) of disk.  This parameter is	optional. The
      /etc/disktab file	contains a list	of disk	types and their	operands and
      partitions.  If you want disks that are the same type to have different
      partition	operands, create separate /etc/disktab file entries describ-
      ing each disk, or	edit the disks'	labels after installation with the -e
      option.  See disktab(4) for more information. If your disk type is not
      specified	in the /etc/disktab file, the disklabel	command	uses the
      default partition	information in the driver. You can also	use the	fol-
      lowing command to	display	disk types:


	   # hwmgr -show comp |	grep WWID

	   COMPONENT NAME
	   SCSI-WWID:0410003a:"DEC RZ26L (C) DECPCB=ZG51569480 ; HDA=000051892202"
	   SCSI-WWID:04100024:"COMPAQ HB00931B93 WT7050055125"
	   SCSI-WWID:0c000008:0060-9487-2a12-4ed2

      The preceding output is edited to	show only the COMPONENT	NAME column.
      The disk type is contained in the	quoted string of the worldwide
      identifier (WWID), which is the manufacturer's model information.	This
      data appears under the COMPONENT NAME column. The	first field contains
      the manufacturer's code, such as COMPAQ The second field contains	the
      disk type, such as RZ26L or HB00931B93. The example device shown on the
      last line	of the output contains no information on the disk type.	In
      such cases, you cannot specify a type, and the disklabel command uses
      the default partition information	in the device driver.

      See hwmgr(8) for more information.

  packid
      Specifies	an optional pack identification	string containing up to	16
      characters.  Use quotes (" ") around the packid parameter	if it con-
      tains space characters.

  protofile
      Specifies	a prototype file that is used to create	the label.  This file
      is in the	same format as the output produced when	you read or edit a
      label. You can add comments by preceding the comment string with a
      pound sign (#) and ending	it by using the	newline	character.

  xxboot
      The primary bootstrap program which must be a valid boot file residing
      in the /mdec directory.

  bootxx
      The secondary bootstrap program which must be a valid boot file resid-
      ing in the /mdec directory.

  fstype
      The file system type, which can be any of	the options listed in the
      following	table:

      File System Types


				 Usage Description

      Value of fstype

      unused			 Available for use
      swap			 Swap space
				 UNIX file system

      4.2BSD, ufs, or UFS
      AdvFS

				 AdvFS file system. This string	is case	sen-
				 sistive. You cannot use advfs.
      cdfs			 CDFS file system
      LSMnoprv			 An LSM	nopriv disk
      LSMpriv			 An LSM	private	region
      LSMpubl			 An LSM	public region
      LSMsimp			 An LSM	simple disk
      database			 A database
      raw			 Raw data



DESCRIPTION

  Use the disklabel command to install,	examine, or modify the label on	a
  disk drive or	pack. The disk label contains information about	the disk,
  such as its type and physical	operands. See rz(7) for	information on SCSI
  disk partitions. The diskconfig graphical user interface (GUI) provides an
  alternate way	to label and partition disks. If you need to create custom
  partition sizes on a disk, the diskconfig command provides you with the
  easiest method. See diskconfig(8) for	more information.

  You also use the disklabel command to	do the following tasks:

    +  Change the drive	identification

    +  Modify the size and usage of disk partitions on the drive

    +  Replace a damaged label

    +  Change the bootstrap program

  These	tasks are referred to as formatting operations on other	operating
  systems.

  The disk label is located on one of the first	sectors	of each	disk, which
  is usually block 0 (zero). On	systems	that require a block-zero bootstrap,
  the label is inserted	into the bootstrap program. There are two copies of a
  disk label, one located on the disk and one located in system	memory.
  Because it is	faster to access system	memory than to perform I/O, when a
  system recognizes a disk, it copies the disk label into memory.

  Reading and Writing a	Label


  Use the -r option to read the	label from or write it to the disk directly,
  instead of reading the system's in-memory copy of the	label. When writing a
  label, the in-memory copy is also updated provided the label operands	are
  valid. You must use the -r option if a disk has no label. This option	might
  enable you to	install	a label	on a disk that does not	have kernel support
  for a	label, such as when labels are first installed on a system. You	also
  use the -r option to examine the label on the	specified disk drive. The
  disklabel command displays all of the	operands associated with the drive
  and its partition layout.  If	the disk has no	label or if the	partition
  types	on the disk are	incorrect, the kernel might have constructed or	modi-
  fied the label.

  Use the -w option to write a standard	label on the designated	drive. You
  must specify the disk	name. The type and packid arguments are	optional. If
  you specify the -r option with the -w	option,	the disk sectors that contain
  the label and	bootstrap are written directly;	otherwise the existing label
  is updated in	place without modifying	the bootstrap.	In either case,	the
  kernel's in-memory label is replaced.	You can	specify	alternate versions of
  the bootstrap	files, using the xxboot	and bootxx arguments.  If an alter-
  nate bootstrap is not	specified, the standard	bootstrap is used. See Speci-
  fying	Bootstrap Programs for more information.

  The -wr options create a bootable disk by default and	you must specify the
  -n option to create a	non bootable disk label. When using the	-n option,
  you can choose to specify the	disk, the type,	and the	packid depending on
  how you want the disk	labeled.

  The -N option	disables writing to the	disk pack label	area. The -W option
  enables writing to the disk pack label area. The label sector	is always
  write-protected when the drive is first opened; the write-enable option set
  by -W	persists only until all	partitions on the drive	are closed.

  Specifying Bootstrap Programs


  If you  specify the -ffilename option	with the -w option, the	disk label is
  written to the specified image file.	The default bootstrap programs are
  for the CDFS	file system.  You can use alternative bootstrap	programs by
  specifying the -t option and indicating the file system type,	such as	ufs.
  Alternatively, you can specify primary and secondary (xxboot and bootxx)
  boot arguments.

  The bootstrap	programs are located in	the /mdec directory. You can specify
  the file names of the	bootstrap programs in the /etc/disktab file. If	you
  do not specify the names, the	syntax of the default file names is as fol-
  lows:

    +  xxboot -	The primary bootstrap, loaded at block 0 (zero).

    +  bootxx -	The secondary bootstrap,  loaded as follows:

	 -- Blocks 1-15	for the	UFS file system

	 -- Blocks 64-95 for the AdvFS file system

  The replaceable string, xx, specifies	the type of disk, such as, rz or re.
  For example, the names are /mdec/rzboot and /mdec/bootrz for a UFS type rz
  disk.

				     Note

       In Version 5.0 and later	the rz device naming convention	for SCSI
       disks changed to	a dsk device naming convention.	 However, rz
       basenames still apply to	SCSI disks. The	/mdec/*rz* files map to	any
       dsk device. See System Administration for information on	device nam-
       ing. See	hwmgr(8) for information on finding devices and	device names.

  For example, If you specify the -t advfs option when labeling	dsk1, the
  disklabel command uses the /mdec/rzboot.advfs	and /mdec/bootrz.advfs files
  by default.

  Printing a Label


  Use the -p option to print the disklabel operands for	a specified disk from
  the /etc/disktab file	to stdout.  The	type of	disk is	obtained directly by
  querying the disk special file. If there is no matching entry	in the
  /etc/disktab file for	the obtained type, the disklabel command uses the
  default partition information	in the driver.

  If the optional type parameter is specified, it takes	precedence over	the
  disk special file, and the information is obtained from /etc/disktab pro-
  viding a matching entry is found for the specified type.  If no matching
  entry	is found, the disklabel	command	uses the default partition informa-
  tion from the	device driver.

  Editing a Label


  You can edit an existing disk	label by using the -e option. The label	is
  read from the	in-memory kernel copy, or directly from	the disk if you
  specify the -r option. The label is formatted	and then sent to an editor.
  If no	editor is specified with the EDITOR environment	variable, the vi edi-
  tor is used.	If vi is not available,	the ed editor is used.

  If an	unexpected error occurs	during the ed editing session, the following
  message is displayed:

       Warning,	edit session exited abnormally!

  You MUST re-edit the disk label to ensure that the modifications you made
  were saved correctly.

  When the editor terminates, the formatted label is reread and	is used	by
  the disklabel	command	to rewrite the disk label.








  Restoring a Label


  If you specify the -R	option,	the disklabel command restores a disk label
  that was previously formatted	and saved in an	ASCII file. You	can also
  specify a prototype file that	is used	to resotre the label. If you also
  specify the -r option, a block-0 bootstrap is	installed on systems that use
  that type of bootstrap.  You must specify either the disk type or the	names
  of the bootstrap files when labelling	a disk for use on such systems.	See
  the Owner's manual for your system for more information.

  If you replace an existing label with	a new label, the existing partition
  information will be copied to	the new	label if the new label's partition is
  marked unused.  This might cause disklabel to	fail and you can avoid this
  failure by using the -z option to first clear	the disk label before per-
  forming the restoration operation.

  Changing the File System Type


  Use the -s option to change the file system type (fstype) in the disk
  label. Specify the disk partition, such as dsk10c, and the new value for
  the fstype parameter,	such as	ufs.

  If a partition no longer contains valid file system data, use	the -s option
  to set the fstype parameter to unused. Or, if	the fstype parameter is
  unused, but the partition does contain valid data, use the -s	option to set
  a valid value	for the	fstype parameter. This prevents	inadvertent loss of
  data,	as applications	such as	newfs, mkfdmn, voldisk,	and swapon check the
  fstype field in the disk label for the partition usage.

  If a partition is already in use, the	diskabel command might display a
  warning message and the partition file system	type does not changed. You
  can force an override	of this	safety feature by using	the -F option with
  the -s option.

NOTES

    +  The kernel device drivers do not	allow the size of a disk partition to
       be decreased or the offset of a partition to be changed while the par-
       tition is open.	Some device drivers create a label containing only a
       single large partition if a disk	is unlabeled; thus the label must be
       written to the a	or c partition of the disk while it is open.  This
       sometimes requires that the desired label be set	in two steps, the
       first one creating at least one other partition,	and the	second one
       setting the label on the	new partition while shrinking the a parti-
       tion.

       The kernel does not allow file system information to be set unused for
       open partitions.	 For example, if you want to set the a partition to
       unused, you must	write the label	using a	different partition (such as
       the c partition).  For example:


	    # disklabel	-w /dev/rdisk/dsk0c

       If a file system	exists for an open partition, the existing file	sys-
       tem information is copied to the	new label.  This preserves the exist-
       ing information without returning an error.

    +  When using LSM, if you try to recover a replaced	mirror disk and	the
       disk has	been replaced with a new disk, the disklabel command fails
       with the	following error, when attempting to write the new label:


	     disklabel:	ioctl DIOCSDINFO: open partition would move or shrink

       Remove the disk from LSM	before attempting to write the new label:


	    # voldisk rm dsk8
	    # disklabel	-wr dsk8



EXAMPLES

   1.  If you enter the	disklabel command but do not specify any options, the
       following command usage help is displayed:


	    #  disklabel
	    Usage:
	      Read 'in-memory copy' of label:
		 disklabel disk

	      Read 'on-disk copy' of label:
		 disklabel -r disk

	      Read label from image file:
		 disklabel [-r]	-f filename

	      Write over existing label:
		 disklabel -w  disk [type [packid]]

	      Write initial label on disk:
		 disklabel -wr [-n] [-t	{advfs | ufs}] disk [type [packid]
		  [xxboot bootxx]]

	      Write label to image file:
		 disklabel -wr [-n] [-t	{advfs | ufs | cdfs}] -f filename
		  [packid] [xxboot bootxx]

	      Edit label:
		 disklabel -e [-r] disk

	      Edit label on image file:
		 disklabel -e -f filename

	      Restore label:
		 disklabel -R  [-t {advfs | ufs}] disk protofile
		 disklabel -Rr [-t {advfs | ufs}] disk protofile
		  [type	| xxboot bootxx]

	      Write disable/enable label:
		 disklabel [-N | -W] disk

	      Zero label:
		 disklabel -z disk

	      Set partition fstype:
		 disklabel -s [-F] disk	fstype

	      Print Default label:
		 disklabel -p disk [type]

   2.  The following example indicates which variants of the device special
       file name are acceptable. The disk is labeled with partitions a,	b,
       and g:


	    # disklabel	/dev/disk/dsk1
	    disklabel: /dev/disk/dsk1: No such file or directory
	    # disklabel	/dev/disk/dsk1c
	      disklabel: not a character device: /dev/disk/dsk1c
	    # disklabel	/dev/disk/dsk1a
	      disklabel: not a character device: /dev/disk/dsk1a
	    # disklabel	/dev/rdisk/dsk1
	    disklabel: /dev/rdisk/dsk1:	No such	file or	directory
	    # disklabel	/dev/rdisk/dsk1c
	    # /dev/rdisk/dsk1c:
	    type: SCSI
	    disk: RZ28M
	    label:
	    .
	    .
	    .
	    # disklabel	dsk1
	    # /dev/rdisk/dsk1c:
	    type: SCSI
	    disk: RZ28M
	    label:
	    flags:
	    .
	    .
	    .

	    # disklabel	dsk1g
	    # /dev/rdisk/dsk1g:
	    type: SCSI
	    disk: RZ28M
	    label:
	    .
	    .
	    .
	    # disklabel	/dev/rdisk/dsk1g
	    # /dev/rdisk/dsk1g:
	    type: SCSI
	    disk: RZ28M
	    label:
	    flags:
	    .
	    .
	    .
	    # disklabel	/dev/disk/dsk1g
	      disklabel: not a character device: /dev/disk/dsk1g
	    .
	    .
	    .

   3.  The following example uses only the -r (read) option to read and
       display the on-disk copy	of the disk label:


	    # disklabel	-r dsk1
	    # /dev/rdisk/dsk1c:
	    type: SCSI
	    disk: RZ28M
	    label:
	    flags:
	    bytes/sector: 512
	    sectors/track: 99
	    tracks/cylinder: 16
	    sectors/cylinder: 1584
	    cylinders: 2595
	    sectors/unit: 4110480
	    rpm: 3600
	    interleave:	1
	    trackskew: 0
	    cylinderskew: 0
	    headswitch:	0	    # milliseconds
	    track-to-track seek: 0  # milliseconds
	    drivedata: 0

	    8 partitions:
	    #		 size	    offset    fstype  fsize  bsize   cpg  # ~Cyl values
	      a:       262144		 0    4.2BSD   1024   8192    16  #	 0 - 165*
	      b:       401404	    262144	swap			  #    165*- 418*
	      c:      4110480		 0    unused   1024   8192	  #	 0 - 2594
	      d:      1060869	    663547    unused   1024   8192	  #    418*- 1088*
	      e:      1191936	   1724416    unused   1024   8192	  #   1088*- 1841*
	      f:      1194128	   2916352    unused   1024   8192	  #   1841*- 2594
	      g:      3446932	    663548    4.2BSD   1024   8192    16  #    418*- 2594
	      h:      1790096	   2320384    unused   1024   8192	  #   1464*- 2594


   4.  The following command indicates an error	caused by attempting a label-
       ing operation on	a disk that is in use. In this case, a partition on
       the disk	was still mounted when the command was issued:


	    # disklabel	-rw dsk1
	      disklabel: ioctl DIOCSDINFO: Open	partition would	move or	shrink
		Use alternate partition


   5.  The following example clears the	existing label,	writes a new label,
       and then	displays the current label. This disk is the same disk used
       in Example 3, and you can compare the differences in the	label:


	    # disklabel	-rw dsk1
	    # disklabel	-r dsk1
	    # /dev/rdisk/dsk1c:
	    type: SCSI
	    disk: RZ28M
	    label:
	    flags:
	    bytes/sector: 512
	    sectors/track: 99
	    tracks/cylinder: 16
	    sectors/cylinder: 1584
	    cylinders: 2595
	    sectors/unit: 4110480
	    rpm: 5411
	    interleave:	1
	    trackskew: 12
	    cylinderskew: 25
	    headswitch:	0	    # milliseconds
	    track-to-track seek: 0  # milliseconds
	    drivedata: 0

	    8 partitions:
	    #		 size	    offset    fstype  fsize  bsize   cpg  # ~Cyl values
	      a:       131072		 0    unused	  0	 0	  #	 0 - 82*
	      b:       401408	    131072    unused	  0	 0	  #	82*- 336*
	      c:      4110480		 0    unused	  0	 0	  #	 0 - 2594
	      d:      1191936	    532480    unused	  0	 0	  #    336*- 1088*
	      e:      1191936	   1724416    unused	  0	 0	  #   1088*- 1841*
	      f:      1194128	   2916352    unused	  0	 0	  #   1841*- 2594
	      g:      1787904	    532480    unused	  0	 0	  #    336*- 1464*
	      h:      1790096	   2320384    unused	  0	 0	  #   1464*- 2594

   6.  The following example marks partition dsk1c for use by the UFS file
       system (4.2BSD).	The second command issued attempts to change the
       usage to	swap space but instead returns an error	message	stating	that
       the partition is	in use.	This safety feature prevents you from losing
       data by accidentally overwriting	in-use partitions:


	    # disklabel	-s dsk1	ufs
	    # disklabel	-s dsk1	swap
	      disklabel: /dev/rdisk/dsk1c is marked in use for 4.2BSD by the disklabel.
	      disklabel: Use -F	option to force	an override.

       The following command overrides the safety feature and the output
       shows than usage	of partition dsk1c is changed:


	    #  disklabel -s -F dsk1 swap
	    #  disklabel -r dsk1
	    # /dev/rdisk/dsk1c:
	    type: SCSI
	    disk: RZ28M
	    .
	    .
	    .
	    #		 size	    offset    fstype  fsize  bsize   cpg  # ~Cyl values
	      c:      4110480		 0	swap			  #	 0 - 2594
	    .
	    .
	    .

   7.  The following example marks partition dsk4c as unused, which means it
       is available for	use:


	    # disklabel	-s dsk4c unused

   8.  The following example shows how a disk label is written to a CDFS
       image file and then read	from it:


	    # disklabel	-r dsk1	>> system.image
	    # disklabel	-w -f system.image
	    # disklabel	-f system.image
	    # system.image:
	    type: unknown
	    disk: CDROM
	    label:
	    flags: removeable
	    bytes/sector: 512
	    sectors/track: 2
	    tracks/cylinder: 1
	    sectors/cylinder: 1
	    cylinders: 1
	    sectors/unit: 2
	    rpm: 300
	    interleave:	1
	    trackskew: 0
	    cylinderskew: 0
	    headswitch:	0	    # milliseconds
	    track-to-track seek: 0  # milliseconds
	    drivedata: 0

	    3 partitions:
	    #		size	  offset    fstype  fsize  bsize   cpg	# ~Cyl values
	      a:	   2	       0      CDFS			#      0 - 1
	      b:	   0	       0    unused	0      0	#      0 - 0







FILES

  /dev/disk
      Contains device special files, such as disk0a

  /dev/rdisk
      Contains raw device special files, such as disk1c

  /etc/disktab
      Contains information about disks and drives

  /mdec/xxboot
      Contains primary bootstrap programs

  /mdec/bootxx
      Contains secondary bootstrap programs

SEE ALSO

  Commands: diskconfig(8), hwmgr(8)

  Files: disklabel(4), disktab(4)

  Misc:	rz(7), ra(7)

  Functions: check_usage(3), set_usage(3)