Glossary
Manual No. 775029
G-21
RAID Controller
See RAID Adapter
RAID Levels
Mylex disk array controllers support four RAID Advisory Board-approved
(RAID 0, RAID 1, RAID 3, RAID 5) and two special RAID levels (RAID
0+1, and JBOD).
Level 0
Block “striping” across multiple drives is provided, yielding higher
performance than is possible with individual drives. This level does not
provide any redundancy.
Level 1
Drives are paired and mirrored. All data is 100 percent duplicated on a drive
of equivalent size.
Level 3
Data is “striped” across several physical drives. Maintains parity information
which can be used for data recovery.
Level 5
Data is “striped” across several physical drives. For data redundancy, drives
are encoded with rotated XOR redundancy.
Level 0+1
Combines RAID 0 striping and RAID 1 mirroring. This level provides
redundancy through mirroring.
JBOD
Sometimes referred to as “Just a Bunch of Drives.” Each drive is operated
independently like a normal disk controller, or drives may be spanned and
seen as a single drive. This level does not provide data redundancy.
