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