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

     graid3 -- control utility for RAID3 devices

     graid3 label [-hnrvw] name	prov prov prov ...
     graid3 clear [-v] prov ...
     graid3 configure [-adhnrRvwW] 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

     The graid3	utility	is used	for RAID3 array	configuration.	After a	device
     is	created, all components	are detected and configured automatically.
     All operations such as failure detection, stale component detection,
     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 contain
		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:

		-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.

		-w  Use	verify reading feature.	 When reading from a device in
		    a complete state, also read	data from the parity component
		    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 increased.
		    One	cannot use this	option if the -r option	is also	speci-

     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.

		-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 autosynchronization
		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.

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

     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 device:

	   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

     geom(4), geom(8), mount(8), newfs(8), umount(8), vinum(8)

     The graid3	utility	appeared in FreeBSD 5.3.

     Pawel Jakub Dawidek <>

     There should be a section with an implementation description.

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

FreeBSD	11.1			August 22, 2004			  FreeBSD 11.1


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