How many availability zones should I use?

For production workloads, deploy across at least 2 AZs. For mission-critical applications, use 3 AZs. Single-AZ is acceptable only for development and testing environments.

Does multi-AZ deployment cost more?

Yes, running instances in multiple AZs increases compute costs proportionally. However, data transfer within a region is typically low-cost. The additional cost is justified by significant availability improvements.

Is the Sydney region sufficient for Australian businesses?

For most businesses, yes. Sydney with 3 AZs provides sufficient redundancy. For extreme disaster recovery needs, deploying also in Melbourne adds geographic separation.

Book Free Assessment Calculator

Availability Zone

A physically separate data centre within a cloud region with independent power, cooling, and networking, providing fault tolerance for cloud applications.

In-Depth Explanation

Availability Zones (AZs) are isolated locations within a cloud region, each with independent infrastructure. They are designed so that a failure in one zone does not affect applications in other zones.

Availability Zone architecture:

Physical separation: Each AZ is in a distinct location, typically kilometres apart
Independent infrastructure: Separate power, cooling, and networking
Low-latency connectivity: AZs within a region connected via high-speed private networks (<2ms latency)
Regional grouping: Each cloud region contains 2-6 availability zones

Australian availability zones:

AWS Sydney (ap-southeast-2): 3 AZs
AWS Melbourne (ap-southeast-4): 3 AZs
Azure Australia East: 3 AZs
Azure Australia Southeast: 3 AZs
Google Cloud Sydney: 3 zones
Google Cloud Melbourne: 3 zones

Multi-AZ deployment patterns:

Active-active: Application runs simultaneously in multiple zones
Active-passive: Primary zone handles traffic, secondary on standby
Database replication: Synchronous replication across zones for data durability
Load balancing: Distribute traffic across instances in different zones

Deploying across multiple AZs within Sydney provides 99.99% uptime versus 99.9% for single-AZ deployments, a significant improvement for business-critical applications.

Business Context

Multi-AZ deployment is essential for business-critical applications, providing automatic failover that keeps services running even when an entire data centre has issues.

How Clever Ops Uses This

Clever Ops architects cloud solutions for Australian businesses with multi-AZ deployment strategies, ensuring business-critical applications maintain high availability and meet uptime requirements.

Example Use Case

"An Australian financial services company deploys across 3 AZs in Sydney. When one zone has networking issues, traffic routes automatically to healthy zones with zero customer impact."