HyperFlex 3.0 introduced the concept of Logical Availability Zones (LAZs). It is an optional feature and is turned off by default. LAZ is not user-configurable at this time and therefore cannot be used to align each rack to a different LAZ.

Logical Availability Zones (LAZs): When using LAZs, one instance of the data is kept within the local LAZ and another instance of the data is kept within another LAZ. Because of this, the cluster can sustain a greater number of node failures until the cluster shuts down to avoid data loss.