In a region, each availability zone is isolated from the other availability zones to prevent reproducing failure or outage across zone boundaries.

Using multiple availability zones provides high availability through redundancy.

Note:

The Consolidated SDDC supports only a single availability zone. Refer to the VMware Validated Design for Software-Defined Data Center if you require multiple availability zones.

Table 1. Characteristics of Availability Zones

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. Common points of failures within a physical data center, like generators and cooling equipment, should not be shared across availability zones. Additionally, these zones should be physically separate so that even uncommon disasters affect only a single availability zone. Availability zones are either two distinct data centers within metro distance or two safety/fire sectors (data halls) within 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) between the zones. This architecture allows the SDDC infrastructure in the availability zone to operate as a single virtual data center within a region.

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