In an SDDC, availability zones are collections of infrastructure components. Availability zones are isolated from each other to prevent the propagation of failure or outage across the data center. Consider using regions to place workloads closer to your customers, comply with data privacy laws and restrictions, and support disaster recovery solutions for the entire SDDC. 

VMware Validated Design for Consolidated SDDC uses a single region with one availability zone. For a multi-region design, see VMware Validated Design for Software-Defined Data Center.