GRAID3(8)						    BSD 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 device is created, all components are detected and configured automati-
     cally.  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:

		-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 complete 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 sector size calculated as multiple of block size and number of regular data components. Big
		    values may decrease performance 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 component and ver-
		    ify 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-
		    fied.

     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 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.  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 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), 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.

BSD
								 January 15, 2012							       BSD