An administrator is creating a hybrid vSAN cluster with six ESXi hosts equally distributed on three server racks. How can this cluster be protected from a single rack failure?

Multiple storage controllers per host improve intra-host I/O redundancy and performance but have no effect on protecting data when an entire rack fails.

Additional disk groups per host increase a single host's capacity and throughput but do not distribute data across racks or protect against a rack-level outage.

Additional flash caching devices in a disk group accelerate read performance within that disk group but provide no rack-level fault tolerance.

Creating one fault domain per rack tells vSAN to treat each rack as a single failure boundary. vSAN then enforces that object replicas and witness components are placed across distinct fault domains, so if one entire rack goes offline the required number of replicas remain accessible on the surviving racks, satisfying the configured failures-to-tolerate policy.