Intel SRCU31 user manual Overview of the RAID Subsystem, Summary of RAID Levels

RAID Features

5.2Overview of the RAID Subsystem

5.2.1Summary of RAID Levels

SRCU31 supports RAID Levels 0,1, 5 and 10. Table 5-1provides a summary of RAID levels.

Table 5-1. Summary of RAID Levels

Intel® Server RAID Controller U3-1 Features and Performance

RAID		Minimum	Maximum	Data	Data
	Description	Number of	Number of			Relative
				Reliability	Transfer
Level		Drives	Drives			I/O Rates
				(protection)	Rates
		Supported	Supported
	Striping of data across
	multiple drives in an array.			No data		Very high for
0	This is a high performance	1	15		Very High	both reads
				protection.
	solution, however there is					and writes.
	no data protection.
	Also known as mirroring.				Reads are	Reads are
					higher than	up to two
	Mirroring refers to the			Highest
					a single	times faster
	100% duplication of data			reliability;
					drive.	than a single
	from one disk to another.			much higher
1		2	2			drive.
	This is a high availability			reliability than
					Writes are	Writes are
	solution, but due to the			a single drive
					about the	about the
	100% duplication, it is also			(no RAID).
					same as a	same as a
	a costly solution.
					single drive.	single drive.
	Striping with parity. Data				Reads are
					similar to	Reads are
	and parity information is			Lower	RAID 0.	similar to
	spread among each drive					RAID 0.
				reliability than
	in the drive group. Parity is
				RAID 1;	Writes are
	equal to the total number
5		3	15	higher
	of disks in the volume				slower than	Writes are
				reliability than
	minus one drive. That one				a single	usually
				a single drive
	drive must be equal to the				drive due to	slower than
				or RAID 0.
	smallest drive capacity in				penalty of	a single
	the array.				writing	drive.
					parity.
	RAID 10 is a combination					Reads are
				Higher		up to two
	of RAID 0 and RAID 1.
				reliability than	Transfer	times faster
	This feature is not user
				RAID 5; much	rates more	than a single
	selectable. It is a function
10		3	15	higher	similar to	drive.
	of how Intel® Server RAID
				reliability than	RAID 1 than	Writes are
	Controller U3-1 writes data
				a single drive	RAID 0.	about the
	on RAID 1 arrays with 3 or
				(no RAID).		same as a
	more disks.
						single drive.

5-6 Intel® Server RAID Controller U3-1 User’s Manual Rev 1.0