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GRAID3(8)		    System Manager's Manual		     GRAID3(8)

NAME
       graid3 -- control utility for RAID3 devices

SYNOPSIS
       graid3 label [-Fhnrvw] [-s blocksize] name prov prov prov ...
       graid3 clear [-v] prov ...
       graid3 configure	[-adfFhnrRvwW] name
       graid3 rebuild [-v] name	prov
       graid3 insert [-hv] [-n number] name prov
       graid3 remove [-v] -n number name
       graid3 stop [-fv] name ...
       graid3 list
       graid3 status
       graid3 load
       graid3 unload

DESCRIPTION
       The  graid3 utility is used for RAID3 array configuration.  After a de-
       vice is created,	all components are detected and	 configured  automati-
       cally.	All  operations	such as	failure	detection, stale component de-
       tection,	rebuild	of stale components, etc. are also done	automatically.
       The graid3 utility uses on-disk metadata	(the provider's	 last  sector)
       to store	all needed information.

       The first argument to graid3 indicates an action	to be performed:

       label	  Create  a  RAID3 device.  The	last given component will con-
		  tain parity data, whilst the others will all contain regular
		  data.	 The number of components must be equal	to  3,	5,  9,
		  17, etc. (2^n	+ 1).

		  Additional options include:

		  -F  Do  not  synchronize  after  a  power  failure or	system
		      crash.  Assumes device is	in consistent state.

		  -h  Hardcode providers' names	in metadata.

		  -n  Turn off autosynchronization of stale components.

		  -r  Use parity component for reading in round-robin fashion.
		      Without this option the parity component is not used  at
		      all  for reading operations when the device is in	a com-
		      plete state.  With this option specified random I/O read
		      operations are even 40% faster, but sequential reads are
		      slower.  One cannot use this option if the -w option  is
		      also specified.

		  -s  Manually	specify	 array	block size. Block size will be
		      set equal	to least common	multiple  of  all  component's
		      sector  sizes and	specified value.  Note that array sec-
		      tor size calculated as multiple of block size and	number
		      of regular data components. Big values may decrease per-
		      formance and compatibility, as all I/O requests have  to
		      be multiple of sector size.

		  -w  Use  verify reading feature.  When reading from a	device
		      in a complete state, also	read data from the parity com-
		      ponent and verify	the data by  comparing	XORed  regular
		      data  with  parity  data.	 If verification fails,	an EIO
		      error   is   returned   and    the    value    of	   the
		      kern.geom.raid3.stat.parity_mismatch   sysctl   is   in-
		      creased.	One cannot use this option if the -r option is
		      also specified.

       clear	  Clear	metadata on the	given providers.

       configure  Configure the	given device.

		  Additional options include:

		  -a  Turn on autosynchronization of stale components.

		  -d  Do not hardcode providers' names in metadata.

		  -f  Synchronize device  after	 a  power  failure  or	system
		      crash.

		  -F  Do  not  synchronize  after  a  power  failure or	system
		      crash.  Assumes device is	in consistent state.

		  -h  Hardcode providers' names	in metadata.

		  -n  Turn off autosynchronization of stale components.

		  -r  Turn on round-robin reading.

		  -R  Turn off round-robin reading.

		  -w  Turn on verify reading.

		  -W  Turn off verify reading.

       rebuild	  Rebuild the given component forcibly.	  If  autosynchroniza-
		  tion	was  not turned	off for	the given device, this command
		  should be unnecessary.

       insert	  Add the given	component to the existing array, if one	of the
		  components was removed previously with the remove command or
		  if one component is missing and will not be connected	again.
		  If no	number is given, new component will be	added  instead
		  of first missed component.

		  Additional options include:

		  -h  Hardcode providers' names	in metadata.

       remove	  Remove  the  given  component	from the given array and clear
		  metadata on it.

       stop	  Stop the given arrays.

		  Additional options include:

		  -f  Stop the given array even	if it is opened.

       list	  See geom(8).

       status	  See geom(8).

       load	  See geom(8).

       unload	  See geom(8).

       Additional options include:

       -v  Be more verbose.

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

EXAMPLES
       Use 3 disks to setup a RAID3 array (with	the round-robin	 reading  fea-
       ture).	Create	a  file	system,	mount it, then unmount it and stop de-
       vice:

	     graid3 label -v -r	data da0 da1 da2
	     newfs /dev/raid3/data
	     mount /dev/raid3/data /mnt
	     ...
	     umount /mnt
	     graid3 stop data
	     graid3 unload

       Create a	RAID3 array, but do not	use the	automatic synchronization fea-
       ture.  Rebuild parity component:

	     graid3 label -n data da0 da1 da2
	     graid3 rebuild data da2

       Replace one data	disk with a brand new one:

	     graid3 remove -n 0	data
	     graid3 insert -n 0	data da5

SEE ALSO
       geom(4),	geom(8), gvinum(8), mount(8), newfs(8),	umount(8)

HISTORY
       The graid3 utility appeared in FreeBSD 5.3.

AUTHORS
       Pawel Jakub Dawidek <pjd@FreeBSD.org>

BUGS
       There should be a section with an implementation	description.

       Documentation for sysctls kern.geom.raid3.* is missing.

FreeBSD	14.3		       January 15, 2012			     GRAID3(8)

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