Avago Technologies AcceleRAID 170LP - Manual (Page 79)

Glossary
Manual No. DB11-000024-00 G-21
RAID Controller
Low cost RAID controllers that use SCSI channels on the motherboard.
RAID Levels
Mylex disk array controllers support four RAID Advisory Board approved
(RAID 0, RAID 1, RAID 3, and RAID 5), two special (RAID 0+1, and
JBOD), and three spanned (RAID 10, 30, and 50) RAID levels. All DAC960,
AcceleRAID, and eXtremeRAID series controllers support these RAID
levels. See also Berkeley RAID Levels.
Level 0: Provides block “striping” across multiple drives, 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.
Level 10: Combines RAID 0 striping and RAID 1 mirroring spanned across
multiple drive groups (super drive group). This level provides redundancy
through mirroring and better performance than Level 1 alone.
Level 30: Data is “striped” across multiple drive groups (super drive group).
Maintains parity information, which can be used for data recovery.
Level 50: Data is “striped” across multiple drive groups (super drive group).
For data redundancy, drives are encoded with rotated XOR redundancy.