Promise Technology 66 Pro user manual Striping/Mirror RAID 0+1

SuperTrak66™ User's Manual Appendix A

Striping/Mirror (RAID 0+1)

Striping/mirroring combines both of the previous array types. It can increase performance by reading and writing data in parallel while protecting data with duplication. A minimum of four drives are needed for striping/mirroring to be installed. With a four-drive disk array, two drives are striped together, and a second pair of striped drives are used to mirror the first pair of striped drives. The data capacity is similar to a standard mirroring array, with half of the total storage capacity dedicated for redundancy. An added plus for using RAID 0+1 is that, in many situations, such an array offers double fault tolerance. Double fault tolerance may allow your data array to continue to operate depending on which two drives fail.

Figure A3: RAID 0+1 striping and mirroring of two drive pairs

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