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APPENDIX
Appendix F
Understanding RAID
RAID is an acronym for Redundant Array of Independent Disks. It
is an array of multiple independent hard disk drives that provides
high performance and fault tolerance. The RAID controller imple-
ments several levels of the Berkeley RAID technology. An appro-
priate RAID level is selected when the volume sets are defined
or created. This decision should be based on the desired disk
capacity, data availability (fault tolerance or redundancy), and
disk performance. The following section discusses the RAID levels
supported by the RAID controllers.
The RAID controllers makes the RAID implementation and the
disks’ physical configuration transparent to the host operating
system. This means that the host operating system drivers and
software utilities are not affected, regardless of the RAID level
selected. Correct installation of the disk array and the control-
ler requires a proper understanding of RAID technology and the
concepts.
RAID 0
RAID 0, also referred to as striping, writes stripes of data across
multiple disk drives instead of just one disk drive. RAID 0 does
not provide any data redundancy, but does offer the best High-
speed data throughput. RAID 0 breaks up data into smaller blocks
and then writes a block to each drive in the array. Disk strip-
ing enhances performance because multiple drives are accessed
simultaneously; the reliability of RAID level 0 is less because the
entire array will fail if any one disk drive fails.
