Dell S100, S300 manual Appendix B

Table B-1. RAID Levels and Characteristics (continued)

RAID Level Main Characteristics Advantages

RAID 1 (mirroring)	Mirrors data on one physical
	disk to another, to provide
	basic redundancy.
	In the event of a single
	physical disk failure a second
	copy of the data exists, which
	can be used to restore the
	data to a new, replacement
	physical disk.

Useful when only two physical disks are available, and when data integrity is more important than storage capacity.

RAID 10 (striped	Combines mirrored and
mirror sets)	striped sets; data are striped
	across mirrored sets of
	physical disks.
	RAID 10 allows multiple
	physical disk failures, up to
	one failed physical disk in
	each mirror that has been
	striped.
	In the event of a single
	physical disk failure (per
	mirror set) a second copy of
	the data exists, which can be
	used to restore the data to a
	new, replacement physical
	disk.

•Offers better performance than a simple mirror because of the additional physical disks.

•Requires twice the disk space of RAID 0 to offer redundancy.

•When a physical disk in a RAID 10 virtual disk fails, the virtual disk is still functional. Data is read from the surviving mirrored disk.

Appendix B

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