VM Disaster Recovery — Azure Site Recovery for IaaS
You are designing a disaster recovery solution for an Azure IaaS workload. The application runs on Azure VMs in a single region and requires a Recovery Point Objective (RPO) of 15 minutes and a Recovery Time Objective (RTO) of 4 hours. Which of the following is the most cost-effective approach to meet these requirements?
Quick Answer
The most cost-effective approach is to deploy Azure Site Recovery to replicate VMs to a secondary region with a replication policy that meets the 15-minute RPO and 4-hour RTO. Azure Site Recovery is purpose-built for disaster recovery of Azure IaaS workloads, offering continuous replication with an RPO as low as 30 seconds and automated failover within minutes, easily satisfying both requirements while minimizing ongoing costs compared to maintaining a full standby environment. On the AZ-305 exam, this scenario tests your ability to distinguish between native DR tools and adjacent services: common traps include choosing geo-redundant storage (which protects storage accounts, not VMs) or Azure Backup (which has a 1-2 hour RPO and slower RTO), while Azure Front Door handles traffic routing, not VM failover. Remember the memory tip: for VM DR, think “Site Recovery for the VM, Backup for the data”—if the question specifies VM-level RPO/RTO, Site Recovery is the answer.
⚠ Common exam trap
Candidates often confuse Azure Backup (which is for archival and long-term recovery) with Azure Site Recovery (which is for replication and rapid failover), leading them to choose Option D despite its inadequate RPO and RTO for disaster recovery scenarios.
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 Azure Site Recovery to replicate VMs to the secondary region with a replication policy that meets the RPO and RTO.
Azure Site Recovery (ASR) provides orchestrated replication of Azure VMs to a secondary region with configurable RPO (as low as 30 seconds) and supports automated failover, meeting the 15-minute RPO and 4-hour RTO requirements. It is the most cost-effective because it replicates only changed blocks and does not require running standby VMs, unlike multi-region active deployments.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Configure geo-redundant storage (GRS) for the VM disks and manually attach them to new VMs in the secondary region.
Why it's wrong here
GRS provides replication for storage accounts but does not provide automated VM failover or meet RTO/RPO requirements.
- ✗
Use Azure Front Door with a back-end pool containing VMs in both regions, and configure health probes to route traffic on failure.
Why it's wrong here
Azure Front Door provides global load balancing and failover for web applications but does not replicate VM state or provide disaster recovery for the VMs themselves.
- ✓
Deploy Azure Site Recovery to replicate VMs to the secondary region with a replication policy that meets the RPO and RTO.
Why this is correct
Azure Site Recovery offers continuous replication with RPO as low as 30 seconds and automated failover minutes, meeting both requirements cost-effectively.
- ✗
Use Azure Backup to back up VMs to a Recovery Services vault in the secondary region and perform restore during failover.
Why it's wrong here
Azure Backup typically has RPO of 1-2 hours and RTO of several hours to days, exceeding the 15-minute RPO.
Go deeper
Related to this question
Learn chapter
Designing Identity Solutions
Key term
Azure Site Recovery
Azure Site Recovery is a Microsoft Azure service that keeps your business applications and data running by automatically replicating them to a secondary location and failing over if the primary site goes down.
Key term
Disaster Recovery Design
Disaster Recovery Design is the process of planning and implementing strategies to restore IT systems and data after a catastrophic failure, ensuring business continuity with minimal downtime and data loss.
About these practice questions
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Same concept, more angles
1 more way this is tested on AZ-305
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. You are designing a disaster recovery solution for a critical application hosted in Azure VMs. The primary region is East US. The application requires a recovery time objective (RTO) of 30 minutes and a recovery point objective (RPO) of 15 minutes. Which Azure service should you use to replicate the VMs?
medium- A.Azure Front Door
- B.Azure Backup
- C.Azure Traffic Manager
- ✓ D.Azure Site Recovery
Why D: Azure Site Recovery (ASR) orchestrates replication, failover, and failback of Azure VMs between regions, meeting the RTO of 30 minutes and RPO of 15 minutes by using continuous replication with crash-consistent or app-consistent snapshots. It is the native Azure service designed specifically for disaster recovery of IaaS workloads with granular recovery objectives.
JA
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.