The data block is subdivided ("striped") and written on the data disks. Stripe parity is generated on Writes, recorded on the parity disk and checked on Reads.
RAID Level 3 requires a minimum of 3 drives to implement
Very high Read data transfer rate
Very high Write data transfer rate
Disk failure has an insignificant impact on throughput
Low ratio of ECC (Parity) disks to data disks means high efficiency
Transaction rate equal to that of a single disk drive at best (if spindles are synchronized)
Controller design is fairly complex
Very difficult and resource intensive to do as a "software" RAID