AZ-305 Design data storage solutions Practice Question
Which THREE of the following are considerations when designing a storage solution for a high-availability application on Azure?
⚠ Common exam trap
Test-takers frequently confuse security features (encryption at rest) or performance optimizations (RAID 0) with high-availability design requirements, leading candidates to select options that are valid in other contexts but irrelevant to uptime and disaster recovery.
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
✓
Recovery Point Objective (RPO) and Recovery Time Objective (RTO)
RPO and RTO are fundamental design considerations for any high-availability application. RPO defines the maximum acceptable data loss (measured in time), which directly influences the choice of backup frequency and replication type (e.g., synchronous vs. asynchronous). RTO defines the maximum acceptable downtime, which dictates the failover mechanism and infrastructure redundancy (e.g., active-passive vs. active-active). Both metrics must be explicitly defined before selecting a storage redundancy tier or disaster recovery strategy.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Recovery Point Objective (RPO) and Recovery Time Objective (RTO)
Why this is correct
RPO and RTO are the foundational metrics that drive the replication and failover architecture for any Azure workload. RPO defines the maximum acceptable data loss measured in time, which dictates the frequency of synchronous or asynchronous replication between source and target. RTO defines the maximum acceptable downtime, which determines the required failover automation, testing cadence, and the choice between active-active and active-passive designs. Together, these metrics force explicit trade-offs between cost, complexity, and resilience, making them the first consideration for designing high availability and disaster recovery.
- ✓
Use of zone-redundant storage (ZRS) for within-region resilience
Why this is correct
Zone-redundant storage (ZRS) synchronously replicates data across three Azure availability zones within the same region, providing resiliency against a complete zone failure. This design ensures that if one zone goes down, the storage remains accessible from the other two zones without requiring any manual intervention or data loss. ZRS is the appropriate choice when the application must maintain availability within a region, but it does not protect against an entire regional outage, which requires geo-redundant storage.
- ✗
Data encryption at rest using Azure Storage Service Encryption
Why it's wrong here
Data encryption at rest using Azure Storage Service Encryption is a mandatory security control that protects data confidentiality when it is stored, but it has no impact on availability or recovery. Encryption operates at the disk and blob level, rendering data unreadable without keys, yet it does not influence replication, failover, or the ability to access data during an outage. This option is incorrect for a high-availability design question because encryption addresses the security pillar of the Azure Well-Architected Framework, not the reliability pillar.
- ✗
Data striping with RAID 0 for performance
Why it's wrong here
Data striping with RAID 0 is an on-premises storage technique that splits data across multiple disks to improve performance, but it provides no redundancy and actually increases the chance of data loss if any disk fails. Azure Storage abstracts the underlying hardware and automatically handles data redundancy across multiple disks, so customers do not implement RAID configurations. In Azure, performance and resilience are achieved through storage replication options (LRS, ZRS, GRS) and tier selection, not through manual disk striping, making RAID 0 irrelevant to high-availability design.
- ✓
Use of geo-redundant storage (GRS) for cross-region disaster recovery
Why this is correct
Geo-redundant storage (GRS) asynchronously replicates data to a paired secondary region, protecting against a complete regional outage by ensuring data is available in a geographically separate location. Because replication is asynchronous, there is a lag window that creates a potential for data loss, so GRS is typically paired with a defined RPO that matches the replication delay. GRS is the correct choice when the solution requires cross-region disaster recovery, but it requires careful planning for failover and failback processes to meet the overall RTO.
Go deeper
Related to this question
Learn chapter
Azure Backup Vault Design
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
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.
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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.