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

NAME
     graid3 -- control utility for RAID3 devices

SYNOPSIS
     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

DESCRIPTION
     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  in-
     formation.

     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 complete
		    state.  With this option specified random  I/O  read  opera-
		    tions  are even 40% faster, but sequential reads are slower.
		    One cannot use this option if the -w option is  also  speci-
		    fied.

		-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 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.

		-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  meta-
		data 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 feature).
     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 feature.
     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), mount(8), newfs(8), umount(8), vinum(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 6.1			 August 22, 2004		       GRAID3(8)
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