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Choosing a RAID Level
When implementing a disk scheme, you have some options to consider. First, you must decide whether you are interested in performance gains (RAID 0) or data redundancy (RAID 1 or 5). Mirroring (RAID 1), for instance, enables the fastest recovery but results in a 50 percent loss of disk space. Likewise, striping with parity (RAID 5) is more economical but requires at least three physical disks and therefore provides more points of potential hardware failure.

Most network administrators prefer the RAID 5 solution, at least on larger servers with multiple drive bays. Because this level is a hybrid of striping and mirroring, it enables greater speed and more redundancy. Mirroring, however, offers the advantage of working well with non-SCSI hardware and is common as a fault-tolerant option on smaller, non-dedicated servers. Striping without parity should be reserved for workstations and servers on which speed considerations are paramount and possible downtime is an acceptable risk. See Figure 9.6 for a graphical comparison.