AZ-900 Describe Azure architecture and services Practice Question
A company stores sensitive customer transaction records in Azure Blob Storage. The records must be available for read access at all times, even if the primary Azure region becomes unavailable. The company initially configured geo-redundant storage (GRS). During a disaster recovery test, the operations team discovers that although data is replicated to a secondary region, they cannot read the data from the secondary region until a Microsoft-initiated failover occurs. The team needs a solution that provides immediate, continuous read access to the replicated data in the secondary region without waiting for a failover. Which Azure Storage replication option should the company use?
⚠ Common exam trap
A common mix-up: candidates confuse GRS with RA-GRS, assuming that geo-replication automatically provides read access to the secondary region, when in fact GRS requires a failover event to enable reads, while RA-GRS explicitly enables continuous read access from the secondary endpoint.
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
✓
Read-access geo-redundant storage (RA-GRS)
RA-GRS extends GRS by enabling read access to the data in the secondary region at all times, without requiring a Microsoft-initiated failover. This ensures that the customer transaction records remain continuously readable from the secondary region, meeting the requirement for immediate read access during a primary region outage.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Locally-redundant storage (LRS)
Why it's wrong here
LRS replicates data three times within a single datacenter in the primary region. It does not provide any replication to a secondary region, so it cannot survive a regional outage, nor does it offer any secondary read access. This option does not meet the disaster recovery requirement.
When this WOULD be correct
A company needs cost-effective storage for non-critical, easily reproducible data that can tolerate a complete datacenter failure, and they do not require cross-region replication or high availability.
- ✗
Zone-redundant storage (ZRS)
Why it's wrong here
ZRS replicates data across availability zones within a single primary region. While it protects against datacenter failures, it does not replicate data to a separate region. Therefore, it cannot provide read access from a secondary region during a regional outage. This option is insufficient for the stated need.
When this WOULD be correct
ZRS would be correct if the question required high availability within a single region, such as protecting against datacenter failures but not regional outages, and did not require cross-region read access.
- ✗
Geo-redundant storage (GRS)
Why it's wrong here
GRS replicates data to a secondary region but only allows read access to that secondary region after a Microsoft-initiated failover occurs. The scenario specifically requires immediate, continuous read access without waiting for a failover. GRS does not meet this requirement.
When this WOULD be correct
A company needs to protect against a regional disaster and can tolerate a short delay in accessing data from the secondary region after a failover. The company does not require immediate read access to the secondary region during normal operations.
- ✓
Read-access geo-redundant storage (RA-GRS)
Why this is correct
RA-GRS provides the same geo-replication as GRS but additionally enables read access to the secondary region at all times, even before any failover event. This meets the company's need for immediate read availability during a regional outage without operational delay.
Option-by-option analysis
Why each answer is right or wrong
Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The AZ-900 exam frequently reuses these exact scenarios with slightly different constraints.
✓Read-access geo-redundant storage (RA-GRS)Correct answer▾
Why this is correct
RA-GRS provides the same geo-replication as GRS but additionally enables read access to the secondary region at all times, even before any failover event. This meets the company's need for immediate read availability during a regional outage without operational delay.
✗Locally-redundant storage (LRS)Wrong answer — click to see why▾
Why this is wrong here
LRS replicates data only within a single datacenter in the primary region, providing no redundancy for regional failures, so it cannot provide read access from a secondary region during an outage.
★ When this WOULD be the correct answer
A company needs cost-effective storage for non-critical, easily reproducible data that can tolerate a complete datacenter failure, and they do not require cross-region replication or high availability.
Why candidates choose this
Candidates may choose LRS because it is the cheapest option and they might overlook the requirement for read access from a secondary region, focusing only on cost savings.
✗Zone-redundant storage (ZRS)Wrong answer — click to see why▾
Why this is wrong here
Zone-redundant storage (ZRS) replicates data synchronously across Azure availability zones within a single region, not across regions. It does not provide read access from a secondary region during a regional outage, which is required for immediate read access without failover.
★ When this WOULD be the correct answer
ZRS would be correct if the question required high availability within a single region, such as protecting against datacenter failures but not regional outages, and did not require cross-region read access.
Why candidates choose this
Candidates may confuse zone-redundancy with geo-redundancy, thinking that 'zones' imply multiple regions, or they may assume ZRS provides similar cross-region read access as RA-GRS.
✗Geo-redundant storage (GRS)Wrong answer — click to see why▾
Why this is wrong here
GRS replicates data to a secondary region but does not provide read access to that data until Microsoft initiates a failover. The question requires immediate read access from the secondary region, which GRS does not support.
★ When this WOULD be the correct answer
A company needs to protect against a regional disaster and can tolerate a short delay in accessing data from the secondary region after a failover. The company does not require immediate read access to the secondary region during normal operations.
Why candidates choose this
Candidates may confuse GRS with RA-GRS, assuming that geo-redundancy automatically includes read access, or they may overlook the specific requirement for immediate read access without failover.
Analysis generated from the official AZ-900blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”
Quick reference
Azure Blob Storage Tier Comparison
| Tier | Storage Cost | Retrieval Cost | Latency | Use Case |
|---|---|---|---|---|
| Hot | Highest | Lowest | Immediate | Active data, frequent reads |
| Cool | Lower | Higher | Immediate | Data accessed < once / month |
| Cold | Lower still | Higher | Immediate | Data accessed < once / quarter |
| Archive | Lowest | Highest + rehydration delay | Hours | Long-term compliance retention |
Go deeper
Related to this question
Learn chapter
Azure Regions and Geographies
Key term
Azure Storage
Azure Storage is Microsoft's cloud-based service for storing data like files, messages, and backups with high durability and scalability.
Key term
Blob storage
Blob storage is a cloud service for storing large amounts of unstructured data, such as text or binary data, like documents, images, and videos.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This AZ-900 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-900 exam.