A vSAN administrator needs to build a vSAN ESA cluster with RAID-5/FTT 1 adaptive storage...

To build a vSAN ESA cluster with RAID-5/FTT 1 adaptive storage policy, the absolute minimum number of hosts that need to be part of that vSAN ESA cluster is 3. This is because the vSAN ESA supports a new RAID-5 erasure coding scheme in a 2+1 configuration, which writes the data in a VM as a stripe consisting of 2 data bits and 1 parity bit, across a minimum of 3 hosts. This scheme can tolerate a single host failure (FTT=1) while consuming 1.5x the capacity of the primary data. This scheme is suitable for smaller vSAN clusters that want to reduce capacity usage without compromising performance12 References: 1: VMware vSAN Specialist v2 ExamPreparation Guide, page 15 2: Adaptive RAID-5 Erasure Coding with the Express Storage Architecture in vSAN 8 3