Promise Technology FastTrak SX Series Version 4.4 - Manual (Page 87)

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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 Performance
Fault
Tolerance
Capacity
No. of
Drives
RAID 0
(Striping)
Highest No
No. Drives x
Smallest Size
2 to 4
RAID 1
(Mirroring)
Normal Yes
Smallest Size
Drive
2
RAID 0+1
(Stripe/Mirror)
High Yes
2X Smallest Size
Drive
4
RAID 5
(Distributed Parity)
High Yes No. Drives -1 3 or 4
JBOD
(Just a Bunch of
Disks)
Normal No Sum of all drives 1 to 4
Figure 82. RAID Levels obtainable with FastTrak SX4000 series and
S150 SX4.