Availability zones and regions have different purposes. Availability zones protect against failures of individual hosts. You can consider regions to place workloads closer to your customers, comply with data privacy laws and restrictions, and support disaster recovery solutions for the entire SDDC.

This design uses a protected region for SDDC management components with one or two availability zones and recovery region with a single availability zone. You can place workloads in each availability zone and region. Usually, multiple availability zones form a single region.

Availability zones

An availability zone is the fault domain of the SDDC. Multiple availability zones can provide continuous availability of an SDDC, minimize down time of services and improve SLAs.

Regions

Regions provide disaster recovery across different SDDC instances. Each region is a separate SDDC instance. The regions have a similar physical layer and virtual infrastructure designs but different naming.

The SDDC in this validated design contains two regions.

The identifiers follow United Nations Code for Trade and Transport Locations(UN/LOCODE) and also contain a numeric instance ID.

Table 1. Availability Zones and Regions in the SDDC
Region Availability Zone and Region Identifier Region-Specific Domain Name Region Description
A SFO01 sfo01.rainpole.local Availability Zone 1 in San Francisco, CA, USA based data center
A SFO02 sfo01.rainpole.local Availability Zone 2 in San Francisco, CA, USA based data center
B LAX01 lax01.rainpole.local Los Angeles, CA, USA based data center
Table 2. Design Decisions оn Availability Zones and Regions

Decision ID

Design Decision

Design Justification

Design Implication

SDDC-PHY-001

In Region A, deploy one or two availability zones to support all SDDC management components and their SLAs.

Supports all SDDC management and compute components for a region.

  • Using a single availability zone 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 in a region.

Supports stretched clusters and application-aware failover for high availability between two physical locations.

Implementing two availability zones increases the solution footprint and can complicate the operational procedures.

SDDC-PHY-002

Use two regions.

Supports the technical requirement of multi-region failover capability according to the design objectives.

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

SDDC-PHY-003

In Region B, deploy one availability zone to support disaster recovery of the SDDC management components.

Supports all SDDC management and tenant components for a region.

You can later add another availability zone to extend and scale out the management and tenant capabilities of the SDDC.

  • Using a single availability zone 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 in a region.