Differential D13335 Diff 36329 sbin/geom/class/raid3/graid3.8

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sbin/geom/class/raid3/graid3.8

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	Do not synchronize after a power failure or system crash.			Do not synchronize after a power failure or system crash.
	Assumes device is in consistent state.			Assumes device is in consistent state.
	.It Fl h			.It Fl h
	Hardcode providers' names in metadata.			Hardcode providers' names in metadata.
	.It Fl n			.It Fl n
	Turn off autosynchronization of stale components.			Turn off autosynchronization of stale components.
	.It Fl r			.It Fl r
	Use parity component for reading in round-robin fashion.			Use parity component for reading in round-robin fashion.
	Without this option the parity component is not used at all for reading operations			Without this option the parity component is not used at all for reading
	when the device is in a complete state.			operations when the device is in a complete state.
	With this option specified random I/O read operations are even 40% faster,			With this option specified random I/O read operations are even 40% faster,
	but sequential reads are slower.			but sequential reads are slower.
	One cannot use this option if the			One cannot use this option if the
	.Fl w			.Fl w
	option is also specified.			option is also specified.
	.It Fl s			.It Fl s
	Manually specify array block size. Block size will be set equal to least			Manually specify array block size.
	common multiple of all component's sector sizes and specified value.			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			Note that array sector size calculated as multiple of block size and number
	of regular data components. Big values may decrease performance and compatibility,			of regular data components.
	as all I/O requests have to be multiple of sector size.			Big values may decrease performance and compatibility, as all I/O requests have
				to be multiple of sector size.
	.It Fl w			.It Fl w
	Use verify reading feature.			Use verify reading feature.
	When reading from a device in a complete state, also read data from the parity component			When reading from a device in a complete state, also read data from the parity
	and verify the data by comparing XORed regular data with parity data.			component and verify the data by comparing XORed regular data with parity data.
	If verification fails, an			If verification fails, an
	.Er EIO			.Er EIO
	error is returned and the value of the			error is returned and the value of the
	.Va kern.geom.raid3.stat.parity_mismatch			.Va kern.geom.raid3.stat.parity_mismatch
	sysctl is increased.			sysctl is increased.
	One cannot use this option if the			One cannot use this option if the
	.Fl r			.Fl r
	option is also specified.			option is also specified.
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