While the resource is valid there are a few mistakes, namely: page 4, Storage space efficiency formula: correct: 1/N page 5, 6x 2-way mirror correct Read IOPS: 3000 correct Write IOPS: 1500 page 6, 4x 3-way mirror correct Streaming read speed: 1200 MB/s page 11, Scenario 3 a SLOG is not a write cache