Availability zones and regions are used for different purposes.

Availability zones

An availability zone is the fault domain of the SDDC. Multiple availability zone scan provide continuous availability of an SDDC, minimize unavailability of services and improve SLAs.


Regions provide disaster recovery across different SDDC instances. This design uses two regions. Each region is a separate SDDC instance. The regions have a similar physical layer design and virtual infrastructure design but different naming. If you are expanding your design to include two regions, see the Business Continuity / Disaster Recovery Design chapter in the VMware Validated Design for the Software-Defined Data Center Reference Architecture document.


This design leverages a single availability zone for a one region deployment, and a single availability zone in each region in the case of a two region deployment.

The two-region design uses the following regions. The region identifier uses United Nations Code for Trade and Transport Locations(UN/LOCODE) along with a numeric instance ID.


Region Identifier

Region-specific Domain Name

Region Description




San Francisco, CA, USA based data center




Los Angeles, CA, USA based data center


Region Identifiers vary based on the locations used in your deployment.

Table 1. Availability Zones and Regions Design Decisions

Decision ID

Design Decision

Design Justification

Design Implication


Per region, a single availability zone that can support all SDDC management components is deployed.

A single availability zone can support all SDDC management and compute components for a region. You can later add another availability zone to extend and scale the management and compute capabilities of the SDDC.

Results in limited redundancy of the overall solution. The single availability zone can become a single point of failure and prevent high-availability design solutions.


Use a single region for the initial deployment. Expand the design to two regions if appropriate.

Supports the technical requirement of multi-region failover capability as outlined in the design objectives.

Having multiple regions requires an increased solution footprint and associated costs.