Installation guide

Glossary
Manual No. 771961 G-9
The appropriate RAID level for a system is selected by the system manager
or integrator. This decision will be based on which of the following are to be
emphasized:
Disk Capacity
Data Availability (redundancy or fault tolerance)
Disk Performance
RAID Levels
Mylex supports four RAID Advisory Board-approved RAID levels (RAID 0,
RAID 1, RAID 3, RAID 5) and several special RAID levels (RAID 0+1,
RAID 00, RAID 10, RAID 30, RAID 50, 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% 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. (Mylex RAID 6)
Levels 00, 10, 30, and 50. Multi-layer RAID levels which span RAID levels
0, 1, 3, and 5 by striping data across drive groups (RAID Drives).
JBOD. Sometimes referred to as “Just a Bunch of Drives.” Each drive is
operated independently like a normal disk drive, or drives may be spanned
and seen as a single drive. This level does not provide data
redundancy. (Mylex RAID 7)