AZ-305 Design business continuity solutions Practice Question
Your company, Fabrikam Inc., operates a global Software-as-a-Service (SaaS) application that provides real-time analytics. The application runs on Azure Kubernetes Service (AKS) with a microservices architecture. The data tier uses Azure Cosmos DB (Core SQL API) with multi-region writes. The application also uses Azure Event Hubs for event ingestion. The business requires a Recovery Time Objective (RTO) of 10 seconds and a Recovery Point Objective (RPO) of 0 for the entire platform. The solution must support active-active configuration across multiple Azure regions. You have been asked to recommend the disaster recovery design. Which option should you recommend?
⚠ Common exam trap
Watch out — candidates often assume Azure Traffic Manager or Azure SQL Database can meet sub-10-second RTO and zero RPO, but they overlook the DNS propagation delays in Traffic Manager and the inherent replication lag in SQL Database auto-failover groups.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Deploy AKS in three regions with Azure Front Door. Use Azure Cosmos DB with multi-region writes. Use Azure Event Hubs with geo-disaster recovery and active-active pattern. Use Azure Cache for Redis Enterprise with active geo-replication.
It meets the strict RTO of 10 seconds and RPO of 0 by using Azure Front Door for global load balancing with health probes, Azure Cosmos DB multi-region writes for zero data loss, Azure Event Hubs with geo-disaster recovery and active-active pattern for continuous event ingestion, and Azure Cache for Redis Enterprise with active geo-replication for synchronized caching across regions. This combination ensures that all components support active-active configuration and can fail over instantly without data loss.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Deploy AKS in three regions with Azure Traffic Manager. Use Azure Cosmos DB with multi-region writes. Use Azure Event Hubs with geo-disaster recovery. Use Azure Cache for Redis Enterprise with active geo-replication.
Why it's wrong here
Azure Traffic Manager is a DNS-based traffic router, so regional failover depends on DNS TTL and client re-resolution, typically taking 30 seconds or more — far exceeding the 10-second RTO. Additionally, Azure Event Hubs geo-disaster recovery alone is an active-passive namespace-level failover mechanism, not an active-active pattern; without paired namespaces and client-side routing, it would still incur downtime and potential event loss during a failover. Even though Cosmos DB multi-region writes and Redis Enterprise active geo-replication provide zero-loss data services, the front-end and event ingestion layers fail the strict recovery-time objective.
- ✗
Deploy AKS in two regions with Azure Front Door. Use Azure Cosmos DB with single write region and auto-failover. Use Azure Service Bus with geo-disaster recovery. Use Azure Cache for Redis Enterprise with active geo-replication.
Why it's wrong here
Cosmos DB with a single write region and auto-failover cannot guarantee RPO=0 during a regional outage because the failover promotes a different region, and any writes that were not yet replicated to the secondary are lost. Azure Service Bus geo-disaster recovery is also active-passive: it requires a manual or scripted namespace failover and does not replicate existing queues/topics or their messages to the secondary unless you set up additional forwarding logic. This combination cannot meet the 10-second RTO or zero-data-loss requirement, and the solution is not truly active-active across regions.
- ✓
Deploy AKS in three regions with Azure Front Door. Use Azure Cosmos DB with multi-region writes. Use Azure Event Hubs with geo-disaster recovery and active-active pattern. Use Azure Cache for Redis Enterprise with active geo-replication.
Why this is correct
This solution meets all stated requirements through active-active replication at every layer. Azure Front Door uses anycast-based global load balancing and continuous health probes, enabling failover in less than the 10-second RTO. Azure Cosmos DB with multi-region writes accepts writes in any region, providing RPO=0 and continuous availability. Azure Event Hubs with geo-disaster recovery and an active-active pattern uses paired namespaces with client-side failover/producer logic to keep event flow uninterrupted. Azure Cache for Redis Enterprise with active geo-replication lets all regions read and write the same cache data with automatic conflict resolution, completing the zero-downtime architecture.
- ✗
Deploy AKS in two regions with Azure Front Door. Use Azure SQL Database with auto-failover groups. Use Azure Event Hubs with geo-disaster recovery. Use Azure Cache for Redis Enterprise with active geo-replication.
Why it's wrong here
Azure SQL Database auto-failover groups are active-passive, relying on asynchronous geo-replication; a regional failover can lose recently committed transactions, so RPO=0 cannot be guaranteed. Azure Event Hubs geo-disaster recovery is likewise active-passive, requiring manual namespace failover and providing no automatic replay of missed events — this breaks the continuous-availability goal. While Azure Front Door offers fast failover and Redis Enterprise active geo-replication is appropriate, the relational and event services force a failover model rather than a true active-active one, so the architecture cannot meet the required recovery point objective or the 10-second RTO.
Go deeper
Related to this question
Learn chapter
Designing Azure Storage Solutions
Key term
BIA and RPO RTO Design
Business Impact Analysis and the design of Recovery Point Objective and Recovery Time Objective define how much data loss and downtime a business can tolerate after an IT failure, guiding the architecture of backup and disaster recovery systems.
Key term
Cosmos DB Design
Cosmos DB Design is the process of structuring data and choosing configuration settings in Azure Cosmos DB to ensure fast performance, low cost, and scalability for applications.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This AZ-305 practice question is part of Courseiva's free Microsoft certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the AZ-305 exam.