Promise Technology 66 Pro - Manual (Page 128)

SuperTrak66™ User's Manual Appendix A
A-4
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