AZ-305 Question 128
Select 2Your company plans to deploy an online retail application on Azure. You have front-end virtual machines hosting the application and an Azure SQL Database instance for the backend. The application must continue to function if an entire Azure region becomes unavailable. Which two design considerations should you implement to ensure high availability across regions?
- A
Deploy front-end VMs to multiple Availability Zones within a single region
- B
Configure Traffic Manager (or Azure Front Door) in multi-region mode to route traffic across two deployed regions
- C
Use a single Azure SQL Database in a single region with an online backup policy
- D
Set up Active Geo-Replication for Azure SQL Database in a secondary region
Show answer and explanation
Correct answers: B, D
Explanation
To ensure high availability across regional outages, it is best practice to deploy compute resources in multiple regions and couple them with global load balancing solutions such as Azure Traffic Manager or Azure Front Door. In addition, Azure SQL Database supports Active Geo-Replication, a feature designed to provide replication across different Azure regions. These approaches align with Microsoft's recommendations for designing resilient cloud architectures. Refer to Microsoft documentation (e.g., https://learn.microsoft.com/azure/architecture/best-practices/availability) for further guidance.
- A. Incorrect.
Option 1: Deploy front-end VMs to multiple Availability Zones within a single region. Explanation: While this protects you against zonal failures within a single region, it does not address the scenario where the entire region is unavailable. Hence, this alone is insufficient for regional outage protection.
- B. Correct.
Option 2: Configure Traffic Manager (or Azure Front Door) in multi-region mode to route traffic across two deployed regions. Explanation: This is correct. By deploying front-end VMs in two separate regions and using Traffic Manager or Front Door to route requests, the application remains accessible even if one region fails.
- C. Incorrect.
Option 3: Use a single Azure SQL Database in a single region with an online backup policy. Explanation: Relying on a single Azure SQL Database and backups in one region does not ensure immediate failover. You could restore from backups, but this leads to downtime and doesn’t meet high availability requirements in the event of a complete regional outage.
- D. Correct.
Option 4: Set up Active Geo-Replication for Azure SQL Database in a secondary region. Explanation: This is correct. Active Geo-Replication replicates the database to another region in near-real time, allowing a quick failover if the primary region becomes unavailable.