There is a tech validation report out done by the Taneja Group that tested and analyzed FAS storage family SAN efficiency.
In this validation, they looked to find if the NetApp FAS family deliver unique efficiency, and does it deliver more than optimized bytes. In the report, Taneja Group writes on requirements of Storage Foundation. The combination of RAID-DP and WAFL set storage free from physical constraints and provide a foundation to keep storage optimized in any scenario. There is an in-depth look into how RAID-DP and WAFL work in parallel to provide availability and reliability. There is more within this report that looks into 4 dimensions of optimization – performance, capacity, access & resources.