RAID5: The stripe size used by vSAN for RAID5 is 3+1 (33% capacity overhead for data protection) and is independent of the cluster size. The minimum cluster size for RAID5 is 4 nodes.
RAID6: The stripe size used by vSAN for RAID6 is 4+2 (50% capacity overhead for data protection) and is independent of the cluster size. The minimum cluster size for RAID6 is 6 nodes.
RAID5/6 can only be leveraged in vSAN All-flash configurations because of I/O amplification.
Product :
VMware, vSAN [SDS]/7.0 U1, Enterprise
Feature :
Protection Capacity Overhead, Reads/Writes, Data Availability