Appendix A: Raid Concepts - Promise Technology FastTrak SX Series Version 4.4 User Manual

Appendix A: RAID Concepts

RAID is an acronym that stands for Redundant Array of Independent Disks. It is
divided into different numbered Levels. The numbers of these Levels do not
mean that one Level is higher or better than another. Each Level has its own
advantages and shortcomings.
PAM allows you to select the RAID Level when you create an Array. The
available RAID Level selection depends on which Promise product you have
and the number of disk drives available. The table below lists the options.
RAID Level
RAID 0
(Striping)
RAID 1
(Mirroring)
RAID 0+1
(Stripe/Mirror)
RAID 5
(Distributed Parity)
JBOD
(Just a Bunch of
Disks)
Figure 82. RAID Levels obtainable with FastTrak SX4000 series and
Performance
Highest
Normal
High
High
Normal
S150 SX4.
Fault
Tolerance
No. Drives x
No
Smallest Size
Smallest Size
Yes
2X Smallest Size
Yes
Yes No. Drives -1
No Sum of all drives
83
Capacity
Drives
Drive
Drive
No. of
2 to 4
2
4
3 or 4
1 to 4