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.

Availability Zone Characteristic

Description

Outage prevention

You avoid outages and improve SLAs. An outage that is caused by external factors, such as power supply, cooling, and physical integrity, affects only one zone. These factors do not cause outage in other zones except in the case of major disasters.

Reliability

Each availability zone runs on its own physically distinct, independent infrastructure, and is engineered to be highly reliable. Each zone should have independent power, cooling, network, and security. Do not share common points of failures in a physical data center, like generators and cooling equipment, across availability zones. Additionally, these zones should be physically separate so that even uncommon disasters affect only one zone.

Availability zones are either two distinct data centers in a metro distance, or two safety or fire sectors (data halls) in the same large-scale data center.

Distance between zones

Multiple availability zones belong to a single region. The physical distance between availability zones is short enough to offer low, single-digit latency (less than 5 ms) and large bandwidth (10 Gbps or greater) between the zones.

You can operate workloads across multiple availability zones in the same region as if they were part of a single virtual data center. This architecture supports high availability that is suitable for mission critical applications. If the distance between two locations of equipment becomes too large, these locations can no longer function as two availability zones in the same region and must be designed as separate regions.

Regions

Regions provide disaster recovery across different SDDC instances or a location that is closer to your customers. Each region is a separate SDDC instance. The regions have a similar physical layer and virtual infrastructure designs but different naming.

Regions are geographically separate, but latency between them must be 150 ms or lower.

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

Region Identifier and Availability Zone

Region-Specific Domain Name

Region Description

SFO

SFO01

sfo.rainpole.io

Availability Zone 1 in San Francisco, CA, USA based data center

SFO

SFO02

sfo.rainpole.io

Availability Zone 2 in San Francisco, CA, USA based data center

LAX

LAX01

lax.rainpole.io

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-MGMT-PHY-001

In Region SFO, that is 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.

  • A 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-MGMT-PHY-002

For a dual-region SDDC, in Region LAX, that is Region B, deploy one availability zone.

Supports all SDDC management and tenant components for a region, providing support for disaster recovery of the management components

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.

  • A single availability zone can become a single point of failure and prevent high-availability design solutions in a region.