Block failure protection can be achieved by assigning nodes in the same appliance to different Fault Sets.
Fault Sets: When using Fault Sets, one instance of the data is kept within the local Fault Set and another instance of the data is kept within another Fault Set. By applying Fault Sets, rack failure protection can be achieved as well.
Dell EMC, PowerFlex [SDS]/3.5, Enterprise
Rack Failure Protection, Reads/Writes, Data Availability