Consider these guidelines when you configure RAID 5 or RAID 6 erasure coding in a vSAN cluster.
RAID 5 or RAID 6 erasure coding is available only on all-flash disk groups.
On-disk format version 3.0 or later is required to support RAID 5 or RAID 6.
You must have a valid license to enable RAID 5/6 on a cluster.
RAID 5/6 is not supported on stretched clusters.
You can achieve additional space savings by enabling deduplication and compression on the vSAN cluster.