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

NAME
     vinum -- Logical Volume Manager control program

SYNOPSIS
     vinum [command] [-options]

COMMANDS
     attach plex volume	[rename]

     attach subdisk plex [offset] [rename]
	     Attach a plex to a	volume,	or a subdisk to	a plex.

     checkparity [-f] [-v] plex
	     Check the parity blocks of	a RAID-4 or RAID-5 plex.

     concat [-f] [-n name] [-v]	drives
	     Create a concatenated volume from the specified drives.

     create [-f] description-file
	     Create a volume as	described in description-file.

     debug   Cause the volume manager to enter the kernel debugger.

     debug flags
	     Set debugging flags.

     detach [-f] [plex | subdisk]
	     Detach a plex or subdisk from the volume or plex to which it is
	     attached.

     dumpconfig	[drive ...]
	     List the configuration information	stored on the specified
	     drives, or	all drives in the system if no drive names are speci-
	     fied.

     info [-v] [-V]
	     List information about volume manager state.

     init [-S size] [-w] plex |	subdisk
	     Initialize	the contents of	a subdisk or all the subdisks of a
	     plex to all zeros.

     label volume
	     Create a volume label.

     l | list [-r] [-s]	[-v] [-V] [volume | plex | subdisk]
	     List information about specified objects.

     ld	[-r] [-s] [-v] [-V] [drive]
	     List information about drives.

     ls	[-r] [-s] [-v] [-V] [subdisk]
	     List information about subdisks.

     lp	[-r] [-s] [-v] [-V] [plex]
	     List information about plexes.

     lv	[-r] [-s] [-v] [-V] [volume]
	     List information about volumes.

     mirror [-f] [-n name] [-s]	[-v] drives
	     Create a mirrored volume from the specified drives.

     move | mv -f drive	object ...
	     Move the object(s)	to the specified drive.

     printconfig [file]
	     Write a copy of the current configuration to file.

     quit    Exit the vinum utility when running in interactive	mode.  Nor-
	     mally this	would be done by entering the EOF character.

     read disk ...
	     Read the vinum configuration from the specified disks.

     rename [-r] [drive	| subdisk | plex | volume] newname
	     Change the	name of	the specified object.

     rebuildparity [-f]	[-v] [-V] plex
	     Rebuild the parity	blocks of a RAID-4 or RAID-5 plex.

     resetconfig
	     Reset the complete	vinum configuration.

     resetstats	[-r] [volume | plex | subdisk]
	     Reset statistics counters for the specified objects, or for all
	     objects if	none are specified.

     rm	[-f] [-r] volume | plex	| subdisk
	     Remove an object.

     saveconfig
	     Save vinum	configuration to disk after configuration failures.

     setdaemon [value]
	     Set daemon	configuration.

     setstate state [volume | plex | subdisk | drive]
	     Set state without influencing other objects, for diagnostic pur-
	     poses only.

     start   Read configuration	from all vinum drives.

     start [-i interval] [-S size] [-w]	volume | plex |	subdisk
	     Allow the system to access	the objects.

     stop [-f] [volume | plex |	subdisk]
	     Terminate access to the objects, or stop vinum if no parameters
	     are specified.

     stripe [-f] [-n name] [-v]	drives
	     Create a striped volume from the specified	drives.

DESCRIPTION
     The vinum utility communicates with the kernel component of the Vinum
     logical volume manager.  It is designed either for	interactive use, when
     started without command line arguments, or	to execute a single command if
     the command is supplied on	the command line.  In interactive mode,	vinum
     maintains a command line history.

OPTIONS
     vinum commands may	optionally be followed by an option.  Any of the fol-
     lowing options may	be specified with any command, but in some cases the
     options are ignored.  For example,	the stop command ignores the -v	and -V
     options.

     -f	     The -f (``force'')	option overrides safety	checks.	 Use with
	     extreme care.  This option	is for emergency use only.  For	exam-
	     ple, the command

		   rm -f myvolume

	     removes myvolume even if it is open.  Any subsequent access to
	     the volume	will almost certainly cause a panic.

     -i	millisecs
	     When performing the init and start	commands, wait millisecs mil-
	     liseconds between copying each block.  This lowers	the load on
	     the system.

     -n	name
	     Use the -n	option to specify a volume name	to the simplified con-
	     figuration	commands concat, mirror	and stripe.

     -r	     The -r (``recursive'') option is used by the list commands	to
	     display information not only about	the specified objects, but
	     also about	subordinate objects.  For example, in conjunction with
	     the lv command, the -r option will	also show information about
	     the plexes	and subdisks belonging to the volume.

     -s	     The -s (``statistics'') option is used by the list	commands to
	     display statistical information.  The mirror command also uses
	     this option to specify that it should create striped plexes.

     -S	size
	     The -S option specifies the transfer size for the init and	start
	     commands.

     -v	     The -v (``verbose'') option can be	used to	request	more detailed
	     information.

     -V	     The -V (``Very verbose'') option can be used to request more
	     detailed information than the -v option provides.

     -w	     The -w (``wait'') option tells vinum to wait for completion of
	     commands which normally run in the	background, such as init.

COMMANDS IN DETAIL
     vinum commands perform the	following functions:

     attach plex volume	[rename]
     attach subdisk plex [offset] [rename]
	     vinum attach inserts the specified	plex or	subdisk	in a volume or
	     plex.  In the case	of a subdisk, an offset	in the plex may	be
	     specified.	 If it is not, the subdisk will	be attached at the
	     first possible location.  After attaching a plex to a non-empty
	     volume, vinum reintegrates	the plex.

	     If	the keyword rename is specified, vinum renames the object (and
	     in	the case of a plex, any	subordinate subdisks) to fit in	with
	     the default vinum naming convention.  To rename the object	to any
	     other name, use the rename	command.

	     A number of considerations	apply to attaching subdisks:

	     +o	 Subdisks can normally only be attached	to concatenated
		 plexes.

	     +o	 If a striped or RAID-5	plex is	missing	a subdisk (for example
		 after drive failure), it should be replaced by	a subdisk of
		 the same size only.

	     +o	 In order to add further subdisks to a striped or RAID-5 plex,
		 use the -f (force) option.  This will corrupt the data	in the
		 plex.

	     +o	 For concatenated plexes, the offset parameter specifies the
		 offset	in blocks from the beginning of	the plex.  For striped
		 and RAID-5 plexes, it specifies the offset of the first block
		 of the	subdisk: in other words, the offset is the numerical
		 position of the subdisk multiplied by the stripe size.	 For
		 example, in a plex with stripe	size 271k, the first subdisk
		 will have offset 0, the second	offset 271k, the third 542k,
		 etc.  This calculation	ignores	parity blocks in RAID-5
		 plexes.

     checkparity [-f] [-v] plex
	     Check the parity blocks on	the specified RAID-4 or	RAID-5 plex.
	     This operation maintains a	pointer	in the plex, so	it can be
	     stopped and later restarted from the same position	if desired.
	     In	addition, this pointer is used by the rebuildparity command,
	     so	rebuilding the parity blocks need only start at	the location
	     where the first parity problem has	been detected.

	     If	the -f flag is specified, checkparity starts checking at the
	     beginning of the plex.  If	the -v flag is specified, checkparity
	     prints a running progress report.

     concat [-f] [-n name] [-v]	drives
	     The concat	command	provides a simplified alternative to the
	     create command for	creating volumes with a	single concatenated
	     plex.  The	largest	contiguous space available on each drive is
	     used to create the	subdisks for the plexes.

	     Normally, the concat command creates an arbitrary name for	the
	     volume and	its components.	 The name is composed of the text
	     ``vinum'' and a small integer, for	example	``vinum3''.  You can
	     override this with	the -n name option, which assigns the name
	     specified to the volume.  The plexes and subdisks are named after
	     the volume	in the default manner.

	     There is no choice	of name	for the	drives.	 If the	drives have
	     already been initialized as vinum drives, the name	remains.  Oth-
	     erwise the	drives are given names starting	with the text
	     ``vinumdrive'' and	a small	integer, for example ``vinumdrive7''.
	     As	with the create	command, the -f	option can be used to specify
	     that a previous name should be overwritten.  The -v is used to
	     specify verbose output.

	     See the section SIMPLIFIED	CONFIGURATION below for	some examples
	     of	this command.

     create [-f] description-file
	     vinum create is used to create any	object.	 In view of the	rela-
	     tively complicated	relationship and the potential dangers
	     involved in creating a vinum object, there	is no interactive
	     interface to this function.  If you do not	specify	a file name,
	     vinum starts an editor on a temporary file.  If the environment
	     variable EDITOR is	set, vinum starts this editor.	If not,	it
	     defaults to vi.  See the section CONFIGURATION FILE below for
	     more information on the format of this file.

	     Note that the vinum create	function is additive: if you run it
	     multiple times, you will create multiple copies of	all unnamed
	     objects.

	     Normally the create command will not change the names of existing
	     vinum drives, in order to avoid accidentally erasing them.	 The
	     correct way to dispose of no longer wanted	vinum drives is	to
	     reset the configuration with the resetconfig command.  In some
	     cases, however, it	may be necessary to create new data on vinum
	     drives which can no longer	be started.  In	this case, use the
	     create -f command.

     debug   vinum debug, without any arguments, is used to enter the remote
	     kernel debugger.  It is only activated if vinum is	built with the
	     VINUMDEBUG	option.	 This option will stop the execution of	the
	     operating system until the	kernel debugger	is exited.  If remote
	     debugging is set and there	is no remote connection	for a kernel
	     debugger, it will be necessary to reset the system	and reboot in
	     order to leave the	debugger.

     debug flags
	     Set a bit mask of internal	debugging flags.  These	will change
	     without warning as	the product matures; to	be certain, read the
	     header file <sys/dev/vinumvar.h>.	The bit	mask is	composed of
	     the following values:

	     DEBUG_ADDRESSES (1)
		     Show buffer information during requests

	     DEBUG_RESID (4)
		     Go	into debugger in complete_rqe().

	     DEBUG_LASTREQS (8)
		     Keep a circular buffer of last requests.

	     DEBUG_REVIVECONFLICT (16)
		     Print info	about revive conflicts.

	     DEBUG_EOFINFO (32)
		     Print information about internal state when returning an
		     EOF on a striped plex.

	     DEBUG_MEMFREE (64)
		     Maintain a	circular list of the last memory areas freed
		     by	the memory allocator.

	     DEBUG_REMOTEGDB (256)
		     Go	into remote gdb	when the debug command is issued.

	     DEBUG_WARNINGS (512)
		     Print some	warnings about minor problems in the implemen-
		     tation.

     detach [-f] plex
     detach [-f] subdisk
	     vinum detach removes the specified	plex or	subdisk	from the vol-
	     ume or plex to which it is	attached.  If removing the object
	     would impair the data integrity of	the volume, the	operation will
	     fail unless the -f	option is specified.  If the object is named
	     after the object above it (for example, subdisk vol1.p7.s0
	     attached to plex vol1.p7),	the name will be changed by prepending
	     the text ``ex-'' (for example, ex-vol1.p7.s0).  If	necessary, the
	     name will be truncated in the process.

	     detach does not reduce the	number of subdisks in a	striped	or
	     RAID-5 plex.  Instead, the	subdisk	is marked absent, and can
	     later be replaced with the	attach command.

     dumpconfig	[drive ...]

	     vinum dumpconfig shows the	configuration information stored on
	     the specified drives.  If no drive	names are specified,
	     dumpconfig	searches all drives on the system for Vinum partitions
	     and dumps the information.	 If configuration updates are dis-
	     abled, it is possible that	this information is not	the same as
	     the information returned by the list command.  This command is
	     used primarily for	maintenance and	debugging.

     info    vinum info	displays information about vinum memory	usage.	This
	     is	intended primarily for debugging.  With	the -v option, it will
	     give detailed information about the memory	areas in use.

	     With the -V option, info displays information about the last up
	     to	64 I/O requests	handled	by the vinum driver.  This information
	     is	only collected if debug	flag 8 is set.	The format looks like:

	     vinum -> info -V
	     Flags: 0x200    1 opens
	     Total of 38 blocks	malloced, total	memory:	16460
	     Maximum allocs:	   56, malloc table at 0xf0f72dbc

	     Time	      Event	  Buf	     Dev     Offset	     Bytes   SD	     SDoff   Doffset Goffset

	     14:40:00.637758 1VS Write 0xf2361f40    91.3  0x10		   16384
	     14:40:00.639280 2LR Write 0xf2361f40    91.3  0x10		   16384
	     14:40:00.639294 3RQ Read  0xf2361f40    4.39   0x104109	    8192    19	    0	    0	    0
	     14:40:00.639455 3RQ Read  0xf2361f40    4.23   0xd2109	    8192    17	    0	    0	    0
	     14:40:00.639529 3RQ Read  0xf2361f40    4.15   0x6e109	    8192    16	    0	    0	    0
	     14:40:00.652978 4DN Read  0xf2361f40    4.39   0x104109	    8192    19	    0	    0	    0
	     14:40:00.667040 4DN Read  0xf2361f40    4.15   0x6e109	    8192    16	    0	    0	    0
	     14:40:00.668556 4DN Read  0xf2361f40    4.23   0xd2109	    8192    17	    0	    0	    0
	     14:40:00.669777 6RP Write 0xf2361f40    4.39   0x104109	    8192    19	    0	    0	    0
	     14:40:00.685547 4DN Write 0xf2361f40    4.39   0x104109	    8192    19	    0	    0	    0
	     11:11:14.975184 Lock      0xc2374210    2	    0x1f8001
	     11:11:15.018400 7VS Write 0xc2374210	    0x7c0	    32768   10
	     11:11:15.018456 8LR Write 0xc2374210    13.39  0xcc0c9	    32768
	     11:11:15.046229 Unlock    0xc2374210    2	    0x1f8001

	     The Buf field always contains the address of the user buffer
	     header.  This can be used to identify the requests	associated
	     with a user request, though this is not 100% reliable: theoreti-
	     cally two requests	in sequence could use the same buffer header,
	     though this is not	common.	 The beginning of a request can	be
	     identified	by the event 1VS or 7VS.  The first example above
	     shows the requests	involved in a user request.  The second	is a
	     subdisk I/O request with locking.

	     The Event field contains information related to the sequence of
	     events in the request chain.  The digit 1 to 6 indicates the
	     approximate sequence of events, and the two-letter	abbreviation
	     is	a mnemonic for the location:

	     1VS       (vinumstrategy) shows information about the user
		       request on entry	to vinumstrategy().  The device	number
		       is the vinum device, and	offset and length are the user
		       parameters.  This is always the beginning of a request
		       sequence.

	     2LR       (launch_requests) shows the user	request	just prior to
		       launching the low-level vinum requests in the function
		       launch_requests().  The parameters should be the	same
		       as in the 1VS information.

	     In	the following requests,	Dev is the device number of the	asso-
	     ciated disk partition, Offset is the offset from the beginning of
	     the partition, SD is the subdisk index in vinum_conf, SDoff is
	     the offset	from the beginning of the subdisk, Doffset is the off-
	     set of the	associated data	request, and Goffset is	the offset of
	     the associated group request, where applicable.

	     3RQ       (request) shows one of possibly several low-level vinum
		       requests	which are launched to satisfy the high-level
		       request.	 This information is also logged in
		       launch_requests().

	     4DN       (done) is called	from complete_rqe(), showing the com-
		       pletion of a request.  This completion should match a
		       request launched	either at stage	4DN from
		       launch_requests(), or from complete_raid5_write() at
		       stage 5RD or 6RP.

	     5RD       (RAID-5 data) is	called from complete_raid5_write() and
		       represents the data written to a	RAID-5 data stripe
		       after calculating parity.

	     6RP       (RAID-5 parity) is called from complete_raid5_write()
		       and represents the data written to a RAID-5 parity
		       stripe after calculating	parity.

	     7VS       shows a subdisk I/O request.  These requests are	usu-
		       ally internal to	vinum for operations like initializa-
		       tion or rebuilding plexes.

	     8LR       shows the low-level operation generated for a subdisk
		       I/O request.

	     Lockwait  specifies that the process is waiting for a range lock.
		       The parameters are the buffer header associated with
		       the request, the	plex number and	the block number.  For
		       internal	reasons	the block number is one	higher than
		       the address of the beginning of the stripe.

	     Lock      specifies that a	range lock has been obtained.  The
		       parameters are the same as for the range	lock.

	     Unlock    specifies that a	range lock has been released.  The
		       parameters are the same as for the range	lock.

     init [-S size] [-w] plex |	subdisk
	     vinum init	initializes a subdisk by writing zeroes	to it.	You
	     can initialize all	subdisks in a plex by specifying the plex
	     name.  This is the	only way to ensure consistent data in a	plex.
	     You must perform this initialization before using a RAID-5	plex.
	     It	is also	recommended for	other new plexes.  vinum initializes
	     all subdisks of a plex in parallel.  Since	this operation can
	     take a long time, it is normally performed	in the background.  If
	     you want to wait for completion of	the command, use the -w	(wait)
	     option.

	     Specify the -S option if you want to write	blocks of a different
	     size from the default value of 16 kB.  vinum prints a console
	     message when the initialization is	complete.

     label volume
	     The label command writes a	ufs style volume label on a volume.
	     It	is a simple alternative	to an appropriate call to disklabel.
	     This is needed because some ufs commands still read the disk to
	     find the label instead of using the correct ioctl(2) call to
	     access it.	 vinum maintains a volume label	separately from	the
	     volume data, so this command is not needed	for newfs(8).  This
	     command is	deprecated.

     list [-r] [-V] [volume | plex | subdisk]
     l [-r] [-V] [volume | plex	| subdisk]
     ld	[-r] [-s] [-v] [-V] [drive]
     ls	[-r] [-s] [-v] [-V] [subdisk]
     lp	[-r] [-s] [-v] [-V] [plex]
     lv	[-r] [-s] [-v] [-V] [volume]
	     list is used to show information about the	specified object.  If
	     the argument is omitted, information is shown about all objects
	     known to vinum.  The l command is a synonym for list.

	     The -r option relates to volumes and plexes: if specified,	it
	     recursively lists information for the subdisks and	(for a volume)
	     plexes subordinate	to the objects.	 The commands lv, lp, ls and
	     ld	list only volumes, plexes, subdisks and	drives respectively.
	     This is particularly useful when used without parameters.

	     The -s option causes vinum	to output device statistics, the -v
	     (verbose) option causes some additional information to be output,
	     and the -V	causes considerable additional information to be out-
	     put.

     mirror [-f] [-n name] [-s]	[-v] drives
	     The mirror	command	provides a simplified alternative to the
	     create command for	creating mirrored volumes.  Without any
	     options, it creates a RAID-1 (mirrored) volume with two concate-
	     nated plexes.  The	largest	contiguous space available on each
	     drive is used to create the subdisks for the plexes.  The first
	     plex is built from	the odd-numbered drives	in the list, and the
	     second plex is built from the even-numbered drives.  If the
	     drives are	of different sizes, the	plexes will be of different
	     sizes.

	     If	the -s option is provided, mirror builds striped plexes	with a
	     stripe size of 279	kB.  The size of the subdisks in each plex is
	     the size of the smallest contiguous storage available on any of
	     the drives	which form the plex.  Again, the plexes	may differ in
	     size.

	     Normally, the mirror command creates an arbitrary name for	the
	     volume and	its components.	 The name is composed of the text
	     ``vinum'' and a small integer, for	example	``vinum3''.  You can
	     override this with	the -n name option, which assigns the name
	     specified to the volume.  The plexes and subdisks are named after
	     the volume	in the default manner.

	     There is no choice	of name	for the	drives.	 If the	drives have
	     already been initialized as vinum drives, the name	remains.  Oth-
	     erwise the	drives are given names starting	with the text
	     ``vinumdrive'' and	a small	integer, for example ``vinumdrive7''.
	     As	with the create	command, the -f	option can be used to specify
	     that a previous name should be overwritten.  The -v is used to
	     specify verbose output.

	     See the section SIMPLIFIED	CONFIGURATION below for	some examples
	     of	this command.

     mv	-f drive object	...
     move -f drive object ...
	     Move all the subdisks from	the specified objects onto the new
	     drive.  The objects may be	subdisks, drives or plexes.  When
	     drives or plexes are specified, all subdisks associated with the
	     object are	moved.

	     The -f option is required for this	function, since	it currently
	     does not preserve the data	in the subdisk.	 This functionality
	     will be added at a	later date.  In	this form, however, it is
	     suited to recovering a failed disk	drive.

     printconfig [file]
	     Write a copy of the current configuration to file in a format
	     that can be used to recreate the vinum configuration.  Unlike the
	     configuration saved on disk, it includes definitions of the
	     drives.  If you omit file,	vinum writes the list to stdout.

     quit    Exit the vinum utility when running in interactive	mode.  Nor-
	     mally this	would be done by entering the EOF character.

     read disk ...
	     The read command scans the	specified disks	for vinum partitions
	     containing	previously created configuration information.  It
	     reads the configuration in	order from the most recently updated
	     to	least recently updated configuration.  The vinum utility main-
	     tains an up-to-date copy of all configuration information on each
	     disk partition.  You must specify all of the slices in a configu-
	     ration as the parameter to	this command.

	     The read command is intended to selectively load a	vinum configu-
	     ration on a system	which has other	vinum partitions.  If you want
	     to	start all partitions on	the system, it is easier to use	the
	     start command.

	     If	vinum encounters any errors during this	command, it will turn
	     off automatic configuration update	to avoid corrupting the	copies
	     on	disk.  This will also happen if	the configuration on disk
	     indicates a configuration error (for example, subdisks which do
	     not have a	valid space specification).  You can turn the updates
	     on	again with the setdaemon and saveconfig	commands.  Reset bit 2
	     (numerical	value 4) of the	daemon options mask to re-enable con-
	     figuration	saves.

     rebuildparity [-f]	[-v] [-V] plex
	     Rebuild the parity	blocks on the specified	RAID-4 or RAID-5 plex.
	     This operation maintains a	pointer	in the plex, so	it can be
	     stopped and later restarted from the same position	if desired.
	     In	addition, this pointer is used by the checkparity command, so
	     rebuilding	the parity blocks need only start at the location
	     where the first parity problem has	been detected.

	     If	the -f flag is specified, rebuildparity	starts rebuilding at
	     the beginning of the plex.	 If the	-v flag	is specified,
	     rebuildparity first checks	the existing parity blocks prints
	     information about those found to be incorrect before rebuilding.
	     If	the -V flag is specified, rebuildparity	prints a running
	     progress report.

     rename [-r] [drive	| subdisk | plex | volume] newname
	     Change the	name of	the specified object.  If the -r option	is
	     specified,	subordinate objects will be named by the default
	     rules: plex names will be formed by appending .pnumber to the
	     volume name, and subdisk names will be formed by appending
	     .snumber to the plex name.

     resetconfig
	     The resetconfig command completely	obliterates the	vinum configu-
	     ration on a system.  Use this command only	when you want to com-
	     pletely delete the	configuration.	vinum will ask for confirma-
	     tion; you must type in the	words NO FUTURE	exactly	as shown:

		   # vinum resetconfig

		   WARNING!  This command will completely wipe out your	vinum
		   configuration.  All data will be lost.  If you really want
		   to do this, enter the text

		   NO FUTURE
		   Enter text -> NO FUTURE
		   Vinum configuration obliterated

	     As	the message suggests, this is a	last-ditch command.  Don't use
	     it	unless you have	an existing configuration which	you never want
	     to	see again.

     resetstats	[-r] [volume | plex | subdisk]
	     vinum maintains a number of statistical counters for each object.
	     See the header file <sys/dev/vinumvar.h> for more information.
	     Use the resetstats	command	to reset these counters.  In conjunc-
	     tion with the -r option, vinum also resets	the counters of	subor-
	     dinate objects.

     rm	[-f] [-r] volume | plex	| subdisk
	     rm	removes	an object from the vinum configuration.	 Once an
	     object has	been removed, there is no way to recover it.  Normally
	     vinum performs a large amount of consistency checking before
	     removing an object.  The -f option	tells vinum to omit this
	     checking and remove the object anyway.  Use this option with
	     great care: it can	result in total	loss of	data on	a volume.

	     Normally, vinum refuses to	remove a volume	or plex	if it has sub-
	     ordinate plexes or	subdisks respectively.	You can	tell vinum to
	     remove the	object anyway by using the -f option, or you can cause
	     vinum to remove the subordinate objects as	well by	using the -r
	     (recursive) option.  If you remove	a volume with the -r option,
	     it	will remove both the plexes and	the subdisks which belong to
	     the plexes.

     saveconfig
	     Save the current configuration to disk.  Normally this is not
	     necessary,	since vinum automatically saves	any change in configu-
	     ration.  If an error occurs on startup, updates will be disabled.
	     When you reenable them with the setdaemon command,	vinum does not
	     automatically save	the configuration to disk.  Use	this command
	     to	save the configuration.

     setdaemon [value]
	     setdaemon sets a variable bitmask for the vinum daemon.  This
	     command is	temporary and will be replaced.	 Currently, the	bit
	     mask may contain the bits 1 (log every action to syslog) and 4
	     (don't update configuration).  Option bit 4 can be	useful for
	     error recovery.

     setstate state [volume | plex | subdisk | drive]
	     setstate sets the state of	the specified objects to the specified
	     state.  This bypasses the usual consistency mechanism of vinum
	     and should	be used	only for recovery purposes.  It	is possible to
	     crash the system by incorrect use of this command.

     start [-i interval] [-S size] [-w]	[plex |	subdisk]
	     start starts (brings into to the up state)	one or more vinum
	     objects.

	     If	no object names	are specified, vinum scans the disks known to
	     the system	for vinum drives and then reads	in the configuration
	     as	described under	the read commands.  The	vinum drive contains a
	     header with all information about the data	stored on the drive,
	     including the names of the	other drives which are required	in
	     order to represent	plexes and volumes.

	     If	vinum encounters any errors during this	command, it will turn
	     off automatic configuration update	to avoid corrupting the	copies
	     on	disk.  This will also happen if	the configuration on disk
	     indicates a configuration error (for example, subdisks which do
	     not have a	valid space specification).  You can turn the updates
	     on	again with the setdaemon and saveconfig	command.  Reset	bit 4
	     of	the daemon options mask	to re-enable configuration saves.

	     If	object names are specified, vinum starts them.	Normally this
	     operation is only of use with subdisks.  The action depends on
	     the current state of the object:

	     +o	 If the	object is already in the up state, vinum does nothing.

	     +o	 If the	object is a subdisk in the down	or reborn states,
		 vinum changes it to the up state.

	     +o	 If the	object is a subdisk in the empty state,	the change
		 depends on the	subdisk.  If it	is part	of a plex which	is
		 part of a volume which	contains other plexes, vinum places
		 the subdisk in	the reviving state and attempts	to copy	the
		 data from the volume.	When the operation completes, the sub-
		 disk is set into the up state.	 If it is part of a plex which
		 is part of a volume which contains no other plexes, or	if it
		 is not	part of	a plex,	vinum brings it	into the up state
		 immediately.

	     +o	 If the	object is a subdisk in the reviving state, vinum con-
		 tinues	the revive operation offline.  When the	operation com-
		 pletes, the subdisk is	set into the up	state.

	     When a subdisk comes into the up state, vinum automatically
	     checks the	state of any plex and volume to	which it may belong
	     and changes their state where appropriate.

	     If	the object is a	plex, start checks the state of	the subordi-
	     nate subdisks (and	plexes in the case of a	volume)	and starts any
	     subdisks which can	be started.

	     To	start a	plex in	a multi-plex volume, the data must be copied
	     from another plex in the volume.  Since this frequently takes a
	     long time,	it is normally done in the background.	If you want to
	     wait for this operation to	complete (for example, if you are per-
	     forming this operation in a script), use the -w option.

	     Copying data doesn't just take a long time, it can	also place a
	     significant load on the system.  You can specify the transfer
	     size in bytes or sectors with the -S option, and an interval (in
	     milliseconds) to wait between copying each	block with the -i
	     option.  Both of these options lessen the load on the system.

     stop [-f] [volume | plex |	subdisk]
	     If	no parameters are specified, stop removes the vinum kld	and
	     stops vinum(4).  This can only be done if no objects are active.
	     In	particular, the	-f option does not override this requirement.
	     Normally, the stop	command	writes the current configuration back
	     to	the drives before terminating.	This will not be possible if
	     configuration updates are disabled, so vinum will not stop	if
	     configuration updates are disabled.  You can override this	by
	     specifying	the -f option.

	     The stop command can only work if vinum has been loaded as	a kld,
	     since it is not possible to unload	a statically configured
	     driver.  vinum stop will fail if vinum is statically configured.

	     If	object names are specified, stop disables access to the
	     objects.  If the objects have subordinate objects,	the subordi-
	     nate objects must either already be inactive (stopped or in
	     error), or	the -r and -f options must be specified.  This command
	     does not remove the objects from the configuration.  They can be
	     accessed again after a start command.

	     By	default, vinum does not	stop active objects.  For example, you
	     cannot stop a plex	which is attached to an	active volume, and you
	     cannot stop a volume which	is open.  The -f option	tells vinum to
	     omit this checking	and remove the object anyway.  Use this	option
	     with great	care and understanding:	used incorrectly, it can
	     result in serious data corruption.

     stripe [-f] [-n name] [-v]	drives
	     The stripe	command	provides a simplified alternative to the
	     create command for	creating volumes with a	single striped plex.
	     The size of the subdisks is the size of the largest contiguous
	     space available on	all the	specified drives.  The stripe size is
	     fixed at 279 kB.

	     Normally, the stripe command creates an arbitrary name for	the
	     volume and	its components.	 The name is composed of the text
	     ``vinum'' and a small integer, for	example	``vinum3''.  You can
	     override this with	the -n name option, which assigns the name
	     specified to the volume.  The plexes and subdisks are named after
	     the volume	in the default manner.

	     There is no choice	of name	for the	drives.	 If the	drives have
	     already been initialized as vinum drives, the name	remains.  Oth-
	     erwise the	drives are given names starting	with the text
	     ``vinumdrive'' and	a small	integer, for example ``vinumdrive7''.
	     As	with the create	command, the -f	option can be used to specify
	     that a previous name should be overwritten.  The -v is used to
	     specify verbose output.

	     See the section SIMPLIFIED	CONFIGURATION below for	some examples
	     of	this command.

SIMPLIFIED CONFIGURATION
     This section describes a simplified interface to vinum configuration
     using the concat, mirror and stripe commands.  These commands create con-
     venient configurations for	some more normal situations, but they are not
     as	flexible as the	create command.

     See above for the description of the commands.  Here are some examples,
     all performed with	the same collection of disks.  Note that the first
     drive, /dev/da1h, is smaller than the others.  This has an	effect on the
     sizes chosen for each kind	of subdisk.

     The following examples all	use the	-v option to show the commands passed
     to	the system, and	also to	list the structure of the volume.  Without the
     -v	option,	these commands produce no output.

   Volume with a single	concatenated plex
     Use a volume with a single	concatenated plex for the largest possible
     storage without resilience	to drive failures:

     vinum -> concat -v	/dev/da1h /dev/da2h /dev/da3h /dev/da4h
     volume vinum0
       plex name vinum0.p0 org concat
     drive vinumdrive0 device /dev/da1h
	 sd name vinum0.p0.s0 drive vinumdrive0	size 0
     drive vinumdrive1 device /dev/da2h
	 sd name vinum0.p0.s1 drive vinumdrive1	size 0
     drive vinumdrive2 device /dev/da3h
	 sd name vinum0.p0.s2 drive vinumdrive2	size 0
     drive vinumdrive3 device /dev/da4h
	 sd name vinum0.p0.s3 drive vinumdrive3	size 0
     V vinum0		     State: up	     Plexes:	   1 Size:	 2134 MB
     P vinum0.p0	   C State: up	     Subdisks:	   4 Size:	 2134 MB
     S vinum0.p0.s0	     State: up	     D:	vinumdrive0  Size:	  414 MB
     S vinum0.p0.s1	     State: up	     D:	vinumdrive1  Size:	  573 MB
     S vinum0.p0.s2	     State: up	     D:	vinumdrive2  Size:	  573 MB
     S vinum0.p0.s3	     State: up	     D:	vinumdrive3  Size:	  573 MB

     In	this case, the complete	space on all four disks	was used, giving a
     volume 2134 MB in size.

   Volume with a single	striped	plex
     A volume with a single striped plex may give better performance than a
     concatenated plex,	but restrictions on striped plexes can mean that the
     volume is smaller.	 It will also not be resilient to a drive failure:

     vinum -> stripe -v	/dev/da1h /dev/da2h /dev/da3h /dev/da4h
     drive vinumdrive0 device /dev/da1h
     drive vinumdrive1 device /dev/da2h
     drive vinumdrive2 device /dev/da3h
     drive vinumdrive3 device /dev/da4h
     volume vinum0
       plex name vinum0.p0 org striped 279k
	 sd name vinum0.p0.s0 drive vinumdrive0	size 849825b
	 sd name vinum0.p0.s1 drive vinumdrive1	size 849825b
	 sd name vinum0.p0.s2 drive vinumdrive2	size 849825b
	 sd name vinum0.p0.s3 drive vinumdrive3	size 849825b
     V vinum0		     State: up	     Plexes:	   1 Size:	 1659 MB
     P vinum0.p0	   S State: up	     Subdisks:	   4 Size:	 1659 MB
     S vinum0.p0.s0	     State: up	     D:	vinumdrive0  Size:	  414 MB
     S vinum0.p0.s1	     State: up	     D:	vinumdrive1  Size:	  414 MB
     S vinum0.p0.s2	     State: up	     D:	vinumdrive2  Size:	  414 MB
     S vinum0.p0.s3	     State: up	     D:	vinumdrive3  Size:	  414 MB

     In	this case, the size of the subdisks has	been limited to	the smallest
     available disk, so	the resulting volume is	only 1659 MB in	size.

   Mirrored volume with	two concatenated plexes
     For more reliability, use a mirrored, concatenated	volume:

     vinum -> mirror -v	-n mirror /dev/da1h /dev/da2h /dev/da3h	/dev/da4h
     drive vinumdrive0 device /dev/da1h
     drive vinumdrive1 device /dev/da2h
     drive vinumdrive2 device /dev/da3h
     drive vinumdrive3 device /dev/da4h
     volume mirror setupstate
       plex name mirror.p0 org concat
	 sd name mirror.p0.s0 drive vinumdrive0	size 0b
	 sd name mirror.p0.s1 drive vinumdrive2	size 0b
       plex name mirror.p1 org concat
	 sd name mirror.p1.s0 drive vinumdrive1	size 0b
	 sd name mirror.p1.s1 drive vinumdrive3	size 0b
     V mirror		     State: up	     Plexes:	   2 Size:	 1146 MB
     P mirror.p0	   C State: up	     Subdisks:	   2 Size:	  988 MB
     P mirror.p1	   C State: up	     Subdisks:	   2 Size:	 1146 MB
     S vinum0.p0.s0	     State: up	     D:	vinumdrive0  Size:	  414 MB
     S vinum0.p0.s2	     State: up	     D:	vinumdrive2  Size:	  414 MB
     S vinum0.p0.s1	     State: up	     D:	vinumdrive1  Size:	  414 MB
     S vinum0.p0.s3	     State: up	     D:	vinumdrive3  Size:	  414 MB

     This example specifies the	name of	the volume, mirror.  Since one drive
     is	smaller	than the others, the two plexes	are of different size, and the
     last 158 MB of the	volume is non-resilient.  To ensure complete reliabil-
     ity in such a situation, use the create command to	create a volume	with
     988 MB.

   Mirrored volume with	two striped plexes
     Alternatively, use	the -s option to create	a mirrored volume with two
     striped plexes:

     vinum -> mirror -v	-n raid10 -s /dev/da1h /dev/da2h /dev/da3h /dev/da4h
     drive vinumdrive0 device /dev/da1h
     drive vinumdrive1 device /dev/da2h
     drive vinumdrive2 device /dev/da3h
     drive vinumdrive3 device /dev/da4h
     volume raid10 setupstate
       plex name raid10.p0 org striped 279k
	 sd name raid10.p0.s0 drive vinumdrive0	size 849825b
	 sd name raid10.p0.s1 drive vinumdrive2	size 849825b
       plex name raid10.p1 org striped 279k
	 sd name raid10.p1.s0 drive vinumdrive1	size 1173665b
	 sd name raid10.p1.s1 drive vinumdrive3	size 1173665b
     V raid10		     State: up	     Plexes:	   2 Size:	 1146 MB
     P raid10.p0	   S State: up	     Subdisks:	   2 Size:	  829 MB
     P raid10.p1	   S State: up	     Subdisks:	   2 Size:	 1146 MB
     S raid10.p0.s0	     State: up	     PO:	0  B Size:	  414 MB
     S raid10.p0.s1	     State: up	     PO:      279 kB Size:	  414 MB
     S raid10.p1.s0	     State: up	     PO:	0  B Size:	  573 MB
     S raid10.p1.s1	     State: up	     PO:      279 kB Size:	  573 MB

     In	this case, the usable part of the volume is even smaller, since	the
     first plex	has shrunken to	match the smallest drive.

CONFIGURATION FILE
     The vinum utility requires	that all parameters to the create commands
     must be in	a configuration	file.  Entries in the configuration file
     define volumes, plexes and	subdisks, and may be in	free format, except
     that each entry must be on	a single line.

   Scale factors
     Some configuration	file parameters	specify	a size (lengths, stripe
     sizes).  These values can be specified as bytes, or one of	the following
     scale factors may be appended:

     s	     specifies that the	value is a number of sectors of	512 bytes.

     k	     specifies that the	value is a number of kilobytes (1024 bytes).

     m	     specifies that the	value is a number of megabytes (1048576
	     bytes).

     g	     specifies that the	value is a number of gigabytes (1073741824
	     bytes).

     b	     is	used for compatibility with VERITAS.  It stands	for blocks of
	     512 bytes.	 This abbreviation is confusing, since the word
	     ``block'' is used in different meanings, and its use is depre-
	     cated.  Use the keyword 's' instead.

     For example, the value 16777216 bytes can also be written as 16m, 16384k
     or	32768s.

     The configuration file can	contain	the following entries:

     drive name	devicename [options]
	   Define a drive.  The	options	are:

	   device devicename   Specify the device on which the drive resides.
			       devicename must be the name of a	disk parti-
			       tion, for example /dev/da1e or /dev/ad3s2h, and
			       it must be of type vinum.  Do not use the ``c''
			       partition, which	is reserved for	the complete
			       disk.

	   hotspare	       Define the drive	to be a	``hot spare'' drive,
			       which is	maintained to automatically replace a
			       failed drive.  The vinum	utility	does not allow
			       this drive to be	used for any other purpose.
			       In particular, it is not	possible to create
			       subdisks	on it.	This functionality has not
			       been completely implemented.

     volume name [options]
	   Define a volume with	name name.  Options are:

	   plex	plexname       Add the specified plex to the volume.  If
			       plexname	is specified as	*, vinum will look for
			       the definition of the plex as the next possible
			       entry in	the configuration file after the defi-
			       nition of the volume.

	   readpol policy      Define a	read policy for	the volume.  policy
			       may be either round or prefer plexname.	The
			       vinum utility satisfies a read request from
			       only one	of the plexes.	A round	read policy
			       specifies that each read	should be performed
			       from a different	plex in	round-robin fashion.
			       A prefer	read policy reads from the specified
			       plex every time.

	   setupstate	       When creating a multi-plex volume, assume that
			       the contents of all the plexes are consistent.
			       This is normally	not the	case, so by default
			       vinum sets all plexes except the	first one to
			       the faulty state.  Use the start	command	to
			       first bring them	to a consistent	state.	In the
			       case of striped and concatenated	plexes,	how-
			       ever, it	does not normally cause	problems to
			       leave them inconsistent:	when using a volume
			       for a file system or a swap partition, the pre-
			       vious contents of the disks are not of inter-
			       est, so they may	be ignored.  If	you want to
			       take this risk, use the setupstate keyword.  It
			       will only apply to the plexes defined immedi-
			       ately after the volume in the configuration
			       file.  If you add plexes	to a volume at a later
			       time, you must integrate	them manually with the
			       start command.

			       Note that you must use the init command with
			       RAID-5 plexes: otherwise	extreme	data corrup-
			       tion will result	if one subdisk fails.

     plex [options]
	   Define a plex.  Unlike a volume, you	do not need to specify a name
	   for a plex.	The options may	be:

	   name	plexname       Specify the name	of the plex.  Note that	you
			       must use	the keyword name when naming a plex or
			       subdisk.

	   org organization [stripesize]
			       Specify the organization	of the plex.
			       organization can	be one of concat, striped or
			       raid5.  For striped and raid5 plexes, the
			       parameter stripesize must be specified, while
			       for concat it must be omitted.  For type
			       striped,	it specifies the width of each stripe.
			       For type	raid5, it specifies the	size of	a
			       group.  A group is a portion of a plex which
			       stores the parity bits all in the same subdisk.
			       It must be a factor of the plex size (in	other
			       words, the result of dividing the plex size by
			       the stripe size must be an integer), and	it
			       must be a multiple of a disk sector (512
			       bytes).

			       For optimum performance,	stripes	should be at
			       least 128 kB in size: anything smaller will
			       result in a significant increase	in I/O activ-
			       ity due to mapping of individual	requests over
			       multiple	disks.	The performance	improvement
			       due to the increased number of concurrent
			       transfers caused	by this	mapping	will not make
			       up for the performance drop due to the increase
			       in latency.  A good guideline for stripe	size
			       is between 256 kB and 512 kB.  Avoid powers of
			       2, however: they	tend to	cause all superblocks
			       to be placed on the first subdisk.  The simpli-
			       fied commands use a stripe size of 279 kB,
			       which shows a reasonable	distribution of
			       superblocks.

			       A striped plex must have	at least two subdisks
			       (otherwise it is	a concatenated plex), and each
			       must be the same	size.  A RAID-5	plex must have
			       at least	three subdisks,	and each must be the
			       same size.  In practice,	a RAID-5 plex should
			       have at least 5 subdisks.

	   volume volname      Add the plex to the specified volume.  If no
			       volume keyword is specified, the	plex will be
			       added to	the last volume	mentioned in the con-
			       figuration file.

	   sd sdname offset    Add the specified subdisk to the	plex at	offset
			       offset.

     subdisk [options]
	   Define a subdisk.  Options may be:

	   name	name	       Specify the name	of a subdisk.  It is not nec-
			       essary to specify a name	for a subdisk--see
			       OBJECT NAMING above.  Note that you must	spec-
			       ify the keyword name if you wish	to name	a sub-
			       disk.

	   plexoffset offset   Specify the starting offset of the subdisk in
			       the plex.  If not specified, vinum allocates
			       the space immediately after the previous	sub-
			       disk, if	any, or	otherwise at the beginning of
			       the plex.

	   driveoffset offset  Specify the starting offset of the subdisk in
			       the drive.  If not specified, vinum allocates
			       the first contiguous length bytes of free space
			       on the drive.

	   length length       Specify the length of the subdisk.  This	key-
			       word must be specified.	There is no default,
			       but the value 0 may be specified	to mean	``use
			       the largest available contiguous	free area on
			       the drive''.  If	the drive is empty, this means
			       that the	entire drive will be used for the sub-
			       disk.  length may be shortened to len.

	   plex	plex	       Specify the plex	to which the subdisk belongs.
			       By default, the subdisk belongs to the last
			       plex specified.

	   drive drive	       Specify the drive on which the subdisk resides.
			       By default, the subdisk resides on the last
			       drive specified.

	   retryerrors	       Specify that the	subdisk	should not be taken
			       down if an unrecoverable	error occurs.  Nor-
			       mally vinum responds to an unrecoverable	error
			       by making the entire subdisk inaccessible.

EXAMPLE	CONFIGURATION FILE
     # Sample vinum configuration file
     #
     # Our drives
     drive drive1 device /dev/da1h
     drive drive2 device /dev/da2h
     drive drive3 device /dev/da3h
     drive drive4 device /dev/da4h
     drive drive5 device /dev/da5h
     drive drive6 device /dev/da6h
     # A volume	with one striped plex
     volume tinyvol
      plex org striped 279k
       sd length 64m drive drive2
       sd length 64m drive drive4
     volume stripe
      plex org striped 279k
       sd length 512m drive drive2
       sd length 512m drive drive4
     # Two plexes
     volume concat
      plex org concat
       sd length 100m drive drive2
       sd length 50m drive drive4
      plex org concat
       sd length 150m drive drive4
     # A volume	with one striped plex and one concatenated plex
     volume strcon
      plex org striped 279k
       sd length 100m drive drive2
       sd length 100m drive drive4
      plex org concat
       sd length 150m drive drive2
       sd length 50m drive drive4
     # a volume	with a RAID-5 and a striped plex
     # note that the RAID-5 volume is longer by
     # the length of one subdisk
     volume vol5
      plex org striped 491k
       sd length 1000m drive drive2
       sd length 1000m drive drive4
      plex org raid5 273k
       sd length 500m drive drive1
       sd length 500m drive drive2
       sd length 500m drive drive3
       sd length 500m drive drive4
       sd length 500m drive drive5

DRIVE LAYOUT CONSIDERATIONS
     vinum drives are currently	BSD disk partitions.  They must	be of type
     vinum in order to avoid overwriting data used for other purposes.	Use
     disklabel -e to edit a partition type definition.	The following display
     shows a typical partition layout as shown by disklabel(8):

     8 partitions:
     #	      size   offset    fstype	[fsize bsize bps/cpg]
       a:    81920   344064    4.2BSD	     0	   0	 0   # (Cyl.  240*- 297*)
       b:   262144    81920	 swap			     # (Cyl.   57*- 240*)
       c:  4226725	  0    unused	     0	   0	     # (Cyl.	0 - 2955*)
       e:    81920	  0    4.2BSD	     0	   0	 0   # (Cyl.	0 - 57*)
       f:  1900000   425984    4.2BSD	     0	   0	 0   # (Cyl.  297*- 1626*)
       g:  1900741  2325984	vinum	     0	   0	 0   # (Cyl. 1626*- 2955*)

     In	this example, partition	``g'' may be used as a vinum partition.	 Par-
     titions ``a'', ``e'' and ``f'' may	be used	as UFS file systems or ccd
     partitions.  Partition ``b'' is a swap partition, and partition ``c''
     represents	the whole disk and should not be used for any other purpose.

     The vinum utility uses the	first 265 sectors on each partition for	con-
     figuration	information, so	the maximum size of a subdisk is 265 sectors
     smaller than the drive.

LOG FILE
     The vinum utility maintains a log file, by	default
     /var/log/vinum_history, in	which it keeps track of	the commands issued to
     vinum.  You can override the name of this file by setting the environment
     variable VINUM_HISTORY to the name	of the file.

     Each message in the log file is preceded by a date.  The default format
     is	"%e %b %Y %H:%M:%S".  See strftime(3) for further details of the for-
     mat string.  It can be overridden by the environment variable
     VINUM_DATEFORMAT.

HOW TO SET UP VINUM
     This section gives	practical advice about how to implement	a vinum	sys-
     tem.

   Where to put	the data
     The first choice you need to make is where	to put the data.  You need
     dedicated disk partitions for vinum.  They	should be partitions, not
     devices, and they should not be partition ``c''.  For example, good names
     are /dev/da0e or /dev/ad3s4a.  Bad	names are /dev/da0 and /dev/da0s1,
     both of which represent a device, not a partition,	and /dev/ad1c, which
     represents	a complete disk	and should be of type unused.  See the example
     under DRIVE LAYOUT	CONSIDERATIONS above.

   Designing volumes
     The way you set up	vinum volumes depends on your intentions.  There are a
     number of possibilities:

     1.	  You may want to join up a number of small disks to make a reasonable
	  sized	file system.  For example, if you had five small drives	and
	  wanted to use	all the	space for a single volume, you might write a
	  configuration	file like:

		drive d1 device	/dev/da2e
		drive d2 device	/dev/da3e
		drive d3 device	/dev/da4e
		drive d4 device	/dev/da5e
		drive d5 device	/dev/da6e
		volume bigger
		 plex org concat
		   sd length 0 drive d1
		   sd length 0 drive d2
		   sd length 0 drive d3
		   sd length 0 drive d4
		   sd length 0 drive d5

	  In this case,	you specify the	length of the subdisks as 0, which
	  means	``use the largest area of free space that you can find on the
	  drive''.  If the subdisk is the only subdisk on the drive, it	will
	  use all available space.

     2.	  You want to set up vinum to obtain additional	resilience against
	  disk failures.  You have the choice of RAID-1, also called
	  ``mirroring'', or RAID-5, also called	``parity''.

	  To set up mirroring, create multiple plexes in a volume.  For	exam-
	  ple, to create a mirrored volume of 2	GB, you	might create the fol-
	  lowing configuration file:

		drive d1 device	/dev/da2e
		drive d2 device	/dev/da3e
		volume mirror
		 plex org concat
		   sd length 2g	drive d1
		 plex org concat
		   sd length 2g	drive d2

	  When creating	mirrored drives, it is important to ensure that	the
	  data from each plex is on a different	physical disk so that vinum
	  can access the complete address space	of the volume even if a	drive
	  fails.  Note that each plex requires as much data as the complete
	  volume: in this example, the volume has a size of 2 GB, but each
	  plex (and each subdisk) requires 2 GB, so the	total disk storage
	  requirement is 4 GB.

	  To set up RAID-5, create a single plex of type raid5.	 For example,
	  to create an equivalent resilient volume of 2	GB, you	might use the
	  following configuration file:

		drive d1 device	/dev/da2e
		drive d2 device	/dev/da3e
		drive d3 device	/dev/da4e
		drive d4 device	/dev/da5e
		drive d5 device	/dev/da6e
		volume raid
		 plex org raid5	433k
		   sd length 512m drive	d1
		   sd length 512m drive	d2
		   sd length 512m drive	d3
		   sd length 512m drive	d4
		   sd length 512m drive	d5

	  RAID-5 plexes	require	at least three subdisks, one of	which is used
	  for storing parity information and is	lost for data storage.	The
	  more disks you use, the greater the proportion of the	disk storage
	  can be used for data storage.	 In this example, the total storage
	  usage	is 2.5 GB, compared to 4 GB for	a mirrored configuration.  If
	  you were to use the minimum of only three disks, you would require 3
	  GB to	store the information, for example:

		drive d1 device	/dev/da2e
		drive d2 device	/dev/da3e
		drive d3 device	/dev/da4e
		volume raid
		 plex org raid5	433k
		   sd length 1g	drive d1
		   sd length 1g	drive d2
		   sd length 1g	drive d3

	  As with creating mirrored drives, it is important to ensure that the
	  data from each subdisk is on a different physical disk so that vinum
	  can access the complete address space	of the volume even if a	drive
	  fails.

     3.	  You want to set up vinum to allow more concurrent access to a	file
	  system.  In many cases, access to a file system is limited by	the
	  speed	of the disk.  By spreading the volume across multiple disks,
	  you can increase the throughput in multi-access environments.	 This
	  technique shows little or no performance improvement in single-
	  access environments.	The vinum utility uses a technique called
	  ``striping'',	or sometimes RAID-0, to	increase this concurrency of
	  access.  The name RAID-0 is misleading: striping does	not provide
	  any redundancy or additional reliability.  In	fact, it decreases the
	  reliability, since the failure of a single disk will render the vol-
	  ume useless, and the more disks you have, the	more likely it is that
	  one of them will fail.

	  To implement striping, use a striped plex:

		drive d1 device	/dev/da2e
		drive d2 device	/dev/da3e
		drive d3 device	/dev/da4e
		drive d4 device	/dev/da5e
		volume raid
		 plex org striped 433k
		   sd length 512m drive	d1
		   sd length 512m drive	d2
		   sd length 512m drive	d3
		   sd length 512m drive	d4

	  A striped plex must have at least two	subdisks, but the increase in
	  performance is greater if you	have a larger number of	disks.

     4.	  You may want to have the best	of both	worlds and have	both
	  resilience and performance.  This is sometimes called	RAID-10	(a
	  combination of RAID-1	and RAID-0), though again this name is mis-
	  leading.  With vinum you can do this with the	following configura-
	  tion file:

		drive d1 device	/dev/da2e
		drive d2 device	/dev/da3e
		drive d3 device	/dev/da4e
		drive d4 device	/dev/da5e
		volume raid setupstate
		 plex org striped 433k
		   sd length 512m drive	d1
		   sd length 512m drive	d2
		   sd length 512m drive	d3
		   sd length 512m drive	d4
		 plex org striped 433k
		   sd length 512m drive	d4
		   sd length 512m drive	d3
		   sd length 512m drive	d2
		   sd length 512m drive	d1

	  Here the plexes are striped, increasing performance, and there are
	  two of them, increasing reliability.	Note that this example shows
	  the subdisks of the second plex in reverse order from	the first
	  plex.	 This is for performance reasons and will be discussed below.
	  In addition, the volume specification	includes the keyword
	  setupstate, which ensures that all plexes are	up after creation.

   Creating the	volumes
     Once you have created your	configuration files, start vinum and create
     the volumes.  In this example, the	configuration is in the	file
     configfile:

       # vinum create -v configfile
	  1: drive d1 device /dev/da2e
	  2: drive d2 device /dev/da3e
	  3: volume mirror
	  4:  plex org concat
	  5:	sd length 2g drive d1
	  6:  plex org concat
	  7:	sd length 2g drive d2
       Configuration summary

       Drives:	       2 (4 configured)
       Volumes:	       1 (4 configured)
       Plexes:	       2 (8 configured)
       Subdisks:       2 (16 configured)

       Drive d1:       Device /dev/da2e
		       Created on vinum.lemis.com at Tue Mar 23	12:30:31 1999
		       Config last updated Tue Mar 23 14:30:32 1999
		       Size:	  60105216000 bytes (57320 MB)
		       Used:	   2147619328 bytes (2048 MB)
		       Available: 57957596672 bytes (55272 MB)
		       State: up
		       Last error: none
       Drive d2:       Device /dev/da3e
		       Created on vinum.lemis.com at Tue Mar 23	12:30:32 1999
		       Config last updated Tue Mar 23 14:30:33 1999
		       Size:	  60105216000 bytes (57320 MB)
		       Used:	   2147619328 bytes (2048 MB)
		       Available: 57957596672 bytes (55272 MB)
		       State: up
		       Last error: none

       Volume mirror:  Size: 2147483648	bytes (2048 MB)
		       State: up
		       Flags:
		       2 plexes
		       Read policy: round robin

       Plex mirror.p0: Size:   2147483648 bytes	(2048 MB)
		       Subdisks:	1
		       State: up
		       Organization: concat
		       Part of volume mirror
       Plex mirror.p1: Size:   2147483648 bytes	(2048 MB)
		       Subdisks:	1
		       State: up
		       Organization: concat
		       Part of volume mirror

       Subdisk mirror.p0.s0:
		       Size:	   2147483648 bytes (2048 MB)
		       State: up
		       Plex mirror.p0 at offset	0

       Subdisk mirror.p1.s0:
		       Size:	   2147483648 bytes (2048 MB)
		       State: up
		       Plex mirror.p1 at offset	0

     The -v option tells vinum to list the file	as it configures.  Subse-
     quently it	lists the current configuration	in the same format as the list
     -v	command.

   Creating more volumes
     Once you have created the vinum volumes, vinum keeps track	of them	in its
     internal configuration files.  You	do not need to create them again.  In
     particular, if you	run the	create command again, you will create addi-
     tional objects:

     # vinum create sampleconfig
     Configuration summary

     Drives:	     2 (4 configured)
     Volumes:	     1 (4 configured)
     Plexes:	     4 (8 configured)
     Subdisks:	     4 (16 configured)

     D d1		     State: up	     Device /dev/da2e	     Avail: 53224/57320	MB (92%)
     D d2		     State: up	     Device /dev/da3e	     Avail: 53224/57320	MB (92%)

     V mirror		     State: up	     Plexes:	   4 Size:	 2048 MB

     P mirror.p0	   C State: up	     Subdisks:	   1 Size:	 2048 MB
     P mirror.p1	   C State: up	     Subdisks:	   1 Size:	 2048 MB
     P mirror.p2	   C State: up	     Subdisks:	   1 Size:	 2048 MB
     P mirror.p3	   C State: up	     Subdisks:	   1 Size:	 2048 MB

     S mirror.p0.s0	     State: up	     PO:	0  B Size:	 2048 MB
     S mirror.p1.s0	     State: up	     PO:	0  B Size:	 2048 MB
     S mirror.p2.s0	     State: up	     PO:	0  B Size:	 2048 MB
     S mirror.p3.s0	     State: up	     PO:	0  B Size:	 2048 MB

     As	this example (this time	with the -f option) shows, re-running the
     create has	created	four new plexes, each with a new subdisk.  If you want
     to	add other volumes, create new configuration files for them.  They do
     not need to reference the drives that vinum already knows about.  For
     example, to create	a volume raid on the four drives /dev/da1e, /dev/da2e,
     /dev/da3e and /dev/da4e, you only need to mention the other two:

	   drive d3 device /dev/da1e
	   drive d4 device /dev/da4e
	   volume raid
	     plex org raid5 433k
	       sd size 2g drive	d1
	       sd size 2g drive	d2
	       sd size 2g drive	d3
	       sd size 2g drive	d4

     With this configuration file, we get:

     # vinum create newconfig
     Configuration summary

     Drives:	     4 (4 configured)
     Volumes:	     2 (4 configured)
     Plexes:	     5 (8 configured)
     Subdisks:	     8 (16 configured)

     D d1		     State: up	     Device /dev/da2e	     Avail: 51176/57320	MB (89%)
     D d2		     State: up	     Device /dev/da3e	     Avail: 53220/57320	MB (89%)
     D d3		     State: up	     Device /dev/da1e	     Avail: 53224/57320	MB (92%)
     D d4		     State: up	     Device /dev/da4e	     Avail: 53224/57320	MB (92%)

     V mirror		     State: down     Plexes:	   4 Size:	 2048 MB
     V raid		     State: down     Plexes:	   1 Size:	 6144 MB

     P mirror.p0	   C State: init     Subdisks:	   1 Size:	 2048 MB
     P mirror.p1	   C State: init     Subdisks:	   1 Size:	 2048 MB
     P mirror.p2	   C State: init     Subdisks:	   1 Size:	 2048 MB
     P mirror.p3	   C State: init     Subdisks:	   1 Size:	 2048 MB
     P raid.p0		  R5 State: init     Subdisks:	   4 Size:	 6144 MB

     S mirror.p0.s0	     State: up	     PO:	0  B Size:	 2048 MB
     S mirror.p1.s0	     State: up	     PO:	0  B Size:	 2048 MB
     S mirror.p2.s0	     State: up	     PO:	0  B Size:	 2048 MB
     S mirror.p3.s0	     State: up	     PO:	0  B Size:	 2048 MB
     S raid.p0.s0	     State: empty    PO:	0  B Size:	 2048 MB
     S raid.p0.s1	     State: empty    PO:      433 kB Size:	 2048 MB
     S raid.p0.s2	     State: empty    PO:      866 kB Size:	 2048 MB
     S raid.p0.s3	     State: empty    PO:     1299 kB Size:	 2048 MB

     Note the size of the RAID-5 plex: it is only 6 GB,	although together its
     components	use 8 GB of disk space.	 This is because the equivalent	of one
     subdisk is	used for storing parity	data.

   Restarting Vinum
     On	rebooting the system, start vinum with the start command:

	   # vinum start

     This will start all the vinum drives in the system.  If for some reason
     you wish to start only some of them, use the read command.

   Performance considerations
     A number of misconceptions	exist about how	to set up a RAID array for
     best performance.	In particular, most systems use	far too	small a	stripe
     size.  The	following discussion applies to	all RAID systems, not just to
     vinum.

     The FreeBSD block I/O system issues requests of between .5kB and 128 kB;
     a typical mix is somewhere	round 8	kB.  You can't stop any	striping sys-
     tem from breaking a request into two physical requests, and if you	make
     the stripe	small enough, it can be	broken into several.  This will	result
     in	a significant drop in performance: the decrease	in transfer time per
     disk is offset by the order of magnitude greater increase in latency.

     With modern disk sizes and	the FreeBSD I/O	system,	you can	expect to have
     a reasonably small	number of fragmented requests with a stripe size
     between 256 kB and	512 kB;	with correct RAID implementations there	is no
     obvious reason not	to increase the	size to	2 or 4 MB on a large disk.

     When choosing a stripe size, consider that	most current UFS file systems
     have cylinder groups 32 MB	in size.  If you have a	stripe size and	number
     of	disks both of which are	a power	of two,	it is probable that all
     superblocks and inodes will be placed on the same subdisk,	which will
     impact performance	significantly.	Choose an odd number instead, for
     example 479 kB.

     The easiest way to	consider the impact of any transfer in a multi-access
     system is to look at it from the point of view of the potential bottle-
     neck, the disk subsystem: how much	total disk time	does the transfer use?
     Since just	about everything is cached, the	time relationship between the
     request and its completion	is not so important: the important parameter
     is	the total time that the	request	keeps the disks	active,	the time when
     the disks are not available to perform other transfers.  As a result, it
     doesn't really matter if the transfers are	happening at the same time or
     different times.  In practical terms, the time we're looking at is	the
     sum of the	total latency (positioning time	and rotational latency,	or the
     time it takes for the data	to arrive under	the disk heads)	and the	total
     transfer time.  For a given transfer to disks of the same speed, the
     transfer time depends only	on the total size of the transfer.

     Consider a	typical	news article or	web page of 24 kB, which will probably
     be	read in	a single I/O.  Take disks with a transfer rate of 6 MB/s and
     an	average	positioning time of 8 ms, and a	file system with 4 kB blocks.
     Since it's	24 kB, we don't	have to	worry about fragments, so the file
     will start	on a 4 kB boundary.  The number	of transfers required depends
     on	where the block	starts:	it's (S	+ F - 1) / S, where S is the stripe
     size in file system blocks, and F is the file size	in file	system blocks.

     1.	  Stripe size of 4 kB.	You'll have 6 transfers.  Total	subsystem
	  load:	48 ms latency, 2 ms transfer, 50 ms total.

     2.	  Stripe size of 8 kB.	On average, you'll have	3.5 transfers.	Total
	  subsystem load: 28 ms	latency, 2 ms transfer,	30 ms total.

     3.	  Stripe size of 16 kB.	 On average, you'll have 2.25 transfers.
	  Total	subsystem load:	18 ms latency, 2 ms transfer, 20 ms total.

     4.	  Stripe size of 256 kB.  On average, you'll have 1.08 transfers.
	  Total	subsystem load:	8.6 ms latency,	2 ms transfer, 10.6 ms total.

     5.	  Stripe size of 4 MB.	On average, you'll have	1.0009 transfers.
	  Total	subsystem load:	8.01 ms	latency, 2 ms transfer,	10.01 ms
	  total.

     It	appears	that some hardware RAID	systems	have problems with large
     stripes: they appear to always transfer a complete	stripe to or from
     disk, so that a large stripe size will have an adverse effect on perfor-
     mance.  The vinum utility does not	suffer from this problem: it optimizes
     all disk transfers	and does not transfer unneeded data.

     Note that no well-known benchmark program tests true multi-access condi-
     tions (more than 100 concurrent users), so	it is difficult	to demonstrate
     the validity of these statements.

     Given these considerations, the following factors affect the performance
     of	a vinum	volume:

     +o	 Striping improves performance for multiple access only, since it
	 increases the chance of individual requests being on different
	 drives.

     +o	 Concatenating UFS file	systems	across multiple	drives can also
	 improve performance for multiple file access, since UFS divides a
	 file system into cylinder groups and attempts to keep files in	a sin-
	 gle cylinder group.  In general, it is	not as effective as striping.

     +o	 Mirroring can improve multi-access performance	for reads, since by
	 default vinum issues consecutive reads	to consecutive plexes.

     +o	 Mirroring decreases performance for all writes, whether multi-access
	 or single access, since the data must be written to both plexes.
	 This explains the subdisk layout in the example of a mirroring	con-
	 figuration above: if the corresponding	subdisk	in each	plex is	on a
	 different physical disk, the write commands can be issued in paral-
	 lel, whereas if they are on the same physical disk, they will be per-
	 formed	sequentially.

     +o	 RAID-5	reads have essentially the same	considerations as striped
	 reads,	unless the striped plex	is part	of a mirrored volume, in which
	 case the performance of the mirrored volume will be better.

     +o	 RAID-5	writes are approximately 25% of	the speed of striped writes:
	 to perform the	write, vinum must first	read the data block and	the
	 corresponding parity block, perform some calculations and write back
	 the parity block and the data block, four times as many transfers as
	 for writing a striped plex.  On the other hand, this is offset	by the
	 cost of mirroring, so writes to a volume with a single	RAID-5 plex
	 are approximately half	the speed of writes to a correctly configured
	 volume	with two striped plexes.

     +o	 When the vinum	configuration changes (for example, adding or removing
	 objects, or the change	of state of one	of the objects), vinum writes
	 up to 128 kB of updated configuration to each drive.  The larger the
	 number	of drives, the longer this takes.

   Creating file systems on Vinum volumes
     You do not	need to	run disklabel(8) before	creating a file	system on a
     vinum volume.  Just run newfs(8).	Use the	-v option to state that	the
     device is not divided into	partitions.  For example, to create a file
     system on volume mirror, enter the	following command:

	   # newfs -U /dev/vinum/mirror

     A number of other considerations apply to vinum configuration:

     +o	 There is no advantage in creating multiple drives on a	single disk.
	 Each drive uses 131.5 kB of data for label and	configuration informa-
	 tion, and performance will suffer when	the configuration changes.
	 Use appropriately sized subdisks instead.

     +o	 It is possible	to increase the	size of	a concatenated vinum plex, but
	 currently the size of striped and RAID-5 plexes cannot	be increased.
	 Currently the size of an existing UFS file system also	cannot be
	 increased, but	it is planned to make both plexes and file systems
	 extensible.

STATE MANAGEMENT
     Vinum objects have	the concept of state.  See vinum(4) for	more details.
     They are only completely accessible if their state	is up.	To change an
     object state to up, use the start command.	 To change an object state to
     down, use the stop	command.  Normally other states	are created automati-
     cally by the relationship between objects.	 For example, if you add a
     plex to a volume, the subdisks of the plex	will be	set in the empty
     state, indicating that, though the	hardware is accessible,	the data on
     the subdisk is invalid.  As a result of this state, the plex will be set
     in	the faulty state.

   The `reviving' state
     In	many cases, when you start a subdisk the system	must copy data to the
     subdisk.  Depending on the	size of	the subdisk, this can take a long
     time.  During this	time, the subdisk is set in the	reviving state.	 On
     successful	completion of the copy operation, it is	automatically set to
     the up state.  It is possible for the process performing the revive to be
     stopped and restarted.  The system	keeps track of how far the subdisk has
     been revived, and when the	start command is reissued, the copying contin-
     ues from this point.

     In	order to maintain the consistency of a volume while one	or more	of its
     plexes is being revived, vinum writes to subdisks which have been revived
     up	to the point of	the write.  It may also	read from the plex if the area
     being read	has already been revived.

GOTCHAS
     The following points are not bugs,	and they have good reasons for exist-
     ing, but they have	shown to cause confusion.  Each	is discussed in	the
     appropriate section above.

     1.	  vinum	drives are UNIX	disk partitions	and must have the partition
	  type vinum.  This is different from ccd, which expects partitions of
	  type 4.2BSD.	This behaviour of ccd is an invitation to shoot	your-
	  self in the foot: with ccd you can easily overwrite a	file system.
	  The vinum utility will not permit this.

	  For similar reasons, the vinum start command will not	accept a drive
	  on partition ``c''.  Partition ``c'' is used by the system to	repre-
	  sent the whole disk, and must	be of type unused.  Clearly there is a
	  conflict here, which vinum resolves by not using the ``c'' parti-
	  tion.

     2.	  When you create a volume with	multiple plexes, vinum does not	auto-
	  matically initialize the plexes.  This means that the	contents are
	  not known, but they are certainly not	consistent.  As	a result, by
	  default vinum	sets the state of all newly-created plexes except the
	  first	to faulty.  In order to	synchronize them with the first	plex,
	  you must start them, which causes vinum to copy the data from	a plex
	  which	is in the up state.  Depending on the size of the subdisks
	  involved, this can take a long time.

	  In practice, people aren't too interested in what was	in the plex
	  when it was created, and other volume	managers cheat by setting them
	  up anyway.  The vinum	utility	provides two ways to ensure that newly
	  created plexes are up:

	  +o   Create the plexes	and then synchronize them with vinum start.

	  +o   Create the volume	(not the plex) with the	keyword	setupstate,
	      which tells vinum	to ignore any possible inconsistency and set
	      the plexes to be up.

     3.	  Some of the commands currently supported by vinum are	not really
	  needed.  For reasons which I don't understand, however, I find that
	  users	frequently try the label and resetconfig commands, though
	  especially resetconfig outputs all sort of dire warnings.  Don't use
	  these	commands unless	you have a good	reason to do so.

     4.	  Some state transitions are not very intuitive.  In fact, it's	not
	  clear	whether	this is	a bug or a feature.  If	you find that you
	  can't	start an object	in some	strange	state, such as a reborn	sub-
	  disk,	try first to get it into stopped state,	with the stop or stop
	  -f commands.	If that	works, you should then be able to start	it.
	  If you find that this	is the only way	to get out of a	position where
	  easier methods fail, please report the situation.

     5.	  If you build the kernel module with the -DVINUMDEBUG option, you
	  must also build vinum	with the -DVINUMDEBUG option, since the	size
	  of some data objects used by both components depends on this option.
	  If you don't do so, commands will fail with a	corresponding error
	  message.

     6.	  The vinum read command has a particularly emetic syntax.  Once it
	  was the only way to start vinum, but now the preferred method	is
	  with vinum start.  vinum read	should be used for maintenance pur-
	  poses	only.  Note that its syntax has	changed, and the arguments
	  must be disk slices, such as /dev/da0, not partitions	such as
	  /dev/da0e.

FILES
     /dev/vinum		 directory with	device nodes for vinum objects
     /dev/vinum/control	 control device	for vinum
     /dev/vinum/plex	 directory containing device nodes for vinum plexes
     /dev/vinum/sd	 directory containing device nodes for vinum subdisks

ENVIRONMENT
     VINUM_HISTORY     The name	of the log file, by default
		       /var/log/vinum_history.

     VINUM_DATEFORMAT  The format of dates in the log file, by default "%e %b
		       %Y %H:%M:%S".

     EDITOR	       The name	of the editor to use for editing configuration
		       files, by default vi.

SEE ALSO
     strftime(3), vinum(4), disklabel(8), newfs(8)

     http://www.vinumvm.org/vinum/,
     http://www.vinumvm.org/vinum/how-to-debug.html.

AUTHORS
     Greg Lehey	<grog@lemis.com>

HISTORY
     The vinum utility first appeared in FreeBSD 3.0.  The RAID-5 component of
     vinum was developed for Cybernet Inc. (www.cybernet.com) for its NetMAX
     product.

BUGS
     vinum(4) does not use the geom(4) subsystem so vinum(4) volumes cannot be
     used with GEOM based facilities like gbde(8).

     vinum(4) is unable	to function on devices with a block size other than
     DEV_BSIZE (512), so cannot	be used	on swap-backed md(4) devices.

FreeBSD	9.2			  May 5, 2003			   FreeBSD 9.2

NAME | SYNOPSIS | COMMANDS | DESCRIPTION | OPTIONS | COMMANDS IN DETAIL | SIMPLIFIED CONFIGURATION | CONFIGURATION FILE | EXAMPLE CONFIGURATION FILE | DRIVE LAYOUT CONSIDERATIONS | LOG FILE | HOW TO SET UP VINUM | STATE MANAGEMENT | GOTCHAS | FILES | ENVIRONMENT | SEE ALSO | AUTHORS | HISTORY | BUGS

Want to link to this manual page? Use this URL:
<http://www.freebsd.org/cgi/man.cgi?query=vinum&sektion=8&manpath=FreeBSD+5.4-RELEASE>

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