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

     dkctl -- program to manipulate disks

     dkctl device
     dkctl device command [arg [...]]

     dkctl allows a user or system administrator to manipulate and configure
     disks in various ways.  It	is used	by specifying a	disk to	manipulate,
     the command to perform, and any arguments the command may require.
     device is the disk	(wdN, sdN, ...)	containing the wedges unless noted
     otherwise.	 If dkctl is called without any	command, it displays strategy,
     cache, and	all of the wedges of the specified device.

     The following commands are	supported:

     getcache		 Get and display the cache enables for the specified

     setcache none | r | w | rw	[save]
			 Set the cache enables for the specified device.  The
			 enables are as	follows:

			       none    Disable all caches on the disk.

			       r       Enable the read cache, and disable all
				       other caches on the disk.

			       w       Enable the write	cache, and disable all
				       other caches on the disk.

			       rw      Enable both the read and	write caches
				       on the disk.

			       save    If specified, and the cache enables are
				       savable,	saves the cache	enables	in the
				       disk's non-volatile parameter storage.

     synccache [force]	 Causes	the cache on the disk to be synchronized,
			 flushing all dirty write cache	blocks to the media.
			 If force is specified,	the cache synchronization com-
			 mand will be issued even if the kernel	does not be-
			 lieve that there are any dirty	cache blocks in	the
			 disk's	cache.

     keeplabel [yes | no]
			 Specify to keep or drop the in-core disklabel on the
			 last close of the disk	device.	 (Keep if yes is spec-
			 ified,	drop if	no is specified.)

     badsector flush | list | retry
			 Used for managing the kernel's	bad sector list	for
			 wd(4) devices.	 The software bad sector list is only
			 maintained if the option "WD_SOFTBADSECT" was speci-
			 fied on kernel	configuration.

			       flush	 Clears	the in kernel list of bad sec-

			       list	 Prints	out the	list of	bad sector
					 ranges	recorded by the	kernel.

			       retry	 Flushes the in	kernel list and	then
					 retries all of	the previously
					 recorded bad sectors, causing the
					 list to self update.  This option can
					 only be used with character devices.

     addwedge name startblk blkcnt ptype
			 Define	a "wedge" on the specified disk	starting at
			 block number startblk and spanning blkcnt blocks.
			 You need to create the	partition first	with fdisk(8)
			 or gpt(8), dkctl will just name it.  The wedge	will
			 have the volume name name and the partition type
			 ptype.	 Valid choices for ptype would be unused,
			 swap, ffs, lfs, ext2fs, cd9660, ados, hfs, msdos,
			 filecore, raidframe, ccd, appleufs, ntfs, and cgd.

			 The device name of the	virtual	block device assigned
			 to the	wedge will be displayed	after the wedge	has
			 been successfully created.  See dk(4) for more	infor-
			 mation	about disk wedges.

     delwedge dk	 Delete	the wedge specified by its device name dk from
			 the specified disk.

     getwedgeinfo	 Display information about the specified disk wedge.
			 device	in this	case is	the wedge name.

     listwedges		 List all of the wedges	configured on the specified

     strategy [name]	 Get and set the disk I/O scheduler (buffer queue
			 strategy) on the drive.  If you do not	provide	a name
			 argument, the currently selected strategy will	be
			 shown.	 To set	the bufq strategy, the name argument
			 must be specified.  name must be the name of one of
			 the built-in kernel disk I/O schedulers.  To get the
			 list of supported schedulers, use the following com-

			       $ sysctl	kern.bufq.strategies

     Note: The addwedge	and delwedge commands only modify the in-kernel	repre-
     sentation of disks; for modifying information on the disks	themselves,
     refer to fdisk(8) or gpt(8).

     ioctl(2), dk(4), sd(4), wd(4), disklabel(5), atactl(8), fdisk(8), gpt(8),

     The dkctl command first appeared in NetBSD	1.6.

     The dkctl command was written by Jason R. Thorpe of Wasabi	Systems, Inc.

BSD				January	5, 2011				   BSD


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