High availability is not the same as disaster recovery

Intro:

The scenarios in this example are applicable to any industry that needs to deploy resilient Azure networking built for high availability and disaster recovery. In these scenarios, we look at a multi-region logical architecture layout for a classic Azure virtual network Hub & Spoke, with Express Route, S2S VPN, Azure Firewall and Azure Front Door.

When designing your Azure network to be resilient, you must understand your availability and disaster recovery requirements. How much downtime is acceptable? The amount of downtime is partly a function of cost. How much will potential downtime cost your business? How much should you invest in making the Network highly available and resilient to failure?

High availability and disaster recovery follow some of the same best practices but with different strategies being applied at all levels of the architecture. Some mitigations are more tactical and others more strategic in nature for example:

• Retrying a remote call after a transient network failure.
• Automatically failing over the entire network to a secondary region.
• Having the right monitoring and diagnostics to detect failures when they happen, and to find the root causes

It’s rare for an entire region to experience a disruption, but transient problems such as network congestion are more common so target these issues first, with that said your availability will…