ZRS: Zone-Redundant Storage for Single Region Availability
A finance team stores application blobs in an Azure Storage account. The data must remain available if a single availability zone in the region is lost, and the team does not need automatic read access from another region. Which redundancy option best meets the requirement?
Quick Answer
The answer is Zone-redundant storage (ZRS). ZRS replicates your data synchronously across three Azure availability zones within the same region, so if a single zone fails, your blobs remain available and durable without any manual failover or automatic read access from a secondary region. This directly meets the requirement for single-region availability with zone failure protection. On the AZ-104 exam, this scenario tests your ability to distinguish ZRS from geo-redundant options like GRS or RA-GZRS, which introduce a secondary region and often include read-access features you don’t need. A common trap is choosing GRS because it offers higher durability, but that adds a second region and automatic failover, which the question explicitly excludes. Remember: ZRS = three zones, one region, no secondary. For a quick memory tip, think “ZRS = Zero Remote Secondary” to keep your focus on local zone redundancy.
⚠ Common exam trap
It's easy for candidates to confuse 'availability within a region' with 'disaster recovery across regions,' leading them to choose GRS or RA-GRS when the requirement is only to survive a single availability zone failure, not a full regional outage.
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
✓
Zone-redundant storage (ZRS), which replicates data across availability zones in the same region.
Zone-redundant storage (ZRS) replicates your data synchronously across three Azure availability zones within the primary region. This ensures that if a single zone fails, the data remains available and durable without requiring any manual intervention or failover, meeting the requirement of no automatic read access from another region.
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), which keeps three copies in one datacenter only.
Why it's wrong here
LRS protects against local disk and server failures inside one datacenter, but it does not add zone-level resilience.
- ✓
Zone-redundant storage (ZRS), which replicates data across availability zones in the same region.
Why this is correct
ZRS stores multiple copies of the data across availability zones within one region, so the storage account can remain available if one zone is lost. This matches the requirement for zone failure resiliency without introducing cross-region read access or the extra complexity of geo-failover. It is the least expansive redundancy option that still provides protection against a zone outage.
- ✗
Geo-redundant storage (GRS), which replicates data to a paired region and supports failover.
Why it's wrong here
GRS adds replication to a paired region, which is useful for regional disaster recovery, but the question does not require cross-region continuity.
When this WOULD be correct
A company requires data to survive a regional disaster (e.g., entire region outage) and is willing to fail over manually or automatically to a secondary region. They do not need immediate read access from the secondary region.
- ✗
Read-access geo-redundant storage (RA-GRS), which allows reads from the secondary region.
Why it's wrong here
RA-GRS is designed for workloads that want secondary-region read access. That is unnecessary here.
When this WOULD be correct
A company needs to ensure data is readable even if the primary region becomes unavailable, and they require automatic failover for read operations. For example, a global application that must serve read requests from a secondary region during a primary region outage.
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-104 exam frequently reuses these exact scenarios with slightly different constraints.
✓Zone-redundant storage (ZRS), which replicates data across availability zones in the same region.Correct answer▾
Why this is correct
ZRS stores multiple copies of the data across availability zones within one region, so the storage account can remain available if one zone is lost. This matches the requirement for zone failure resiliency without introducing cross-region read access or the extra complexity of geo-failover. It is the least expansive redundancy option that still provides protection against a zone outage.
✗Geo-redundant storage (GRS), which replicates data to a paired region and supports failover.Wrong answer — click to see why▾
Why this is wrong here
GRS replicates data to a paired region, which provides durability across regions but does not protect against a single availability zone failure within the primary region; it also incurs higher cost and latency than needed.
★ When this WOULD be the correct answer
A company requires data to survive a regional disaster (e.g., entire region outage) and is willing to fail over manually or automatically to a secondary region. They do not need immediate read access from the secondary region.
Why candidates choose this
Candidates may confuse 'zone failure' with 'regional failure' and think GRS offers zone-level protection, or they may over-specify redundancy without considering cost and simplicity.
✗Read-access geo-redundant storage (RA-GRS), which allows reads from the secondary region.Wrong answer — click to see why▾
Why this is wrong here
RA-GRS provides read access to a secondary region, but the requirement states no automatic read access from another region is needed. Additionally, RA-GRS does not protect against a single availability zone loss within the primary region; it only protects against region-level failures.
★ When this WOULD be the correct answer
A company needs to ensure data is readable even if the primary region becomes unavailable, and they require automatic failover for read operations. For example, a global application that must serve read requests from a secondary region during a primary region outage.
Why candidates choose this
Candidates may think RA-GRS offers better availability than ZRS because it includes geo-replication, but they overlook the explicit requirement that no automatic read access from another region is needed, making RA-GRS overkill and not aligned with the question's constraints.
Analysis generated from the official AZ-104blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”
Go deeper
Related to this question
Learn chapter
Managed Identities for Azure Resources
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
Region
A region is a distinct geographic location where a cloud provider operates multiple data centers that are connected by low-latency networks and provide cloud services.
About these practice questions
Courseiva writes every AZ-104 question from scratch — 1,049 in total, each with an explanation and a wrong-answer breakdown. None are copied from real exams or dumps. Learn why practice questions differ from exam dumps →
Same concept, more angles
2 more ways this is tested on AZ-104
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. An application writes transaction logs to a storage account in a region that supports availability zones. The business wants the account to stay available if one datacenter or zone fails, but it does not need a secondary region replica. Which redundancy option should you choose?
medium- A.LRS, because it keeps three copies within a single datacenter and is enough for any zone failure.
- ✓ B.ZRS, because it replicates synchronously across zones in the same region and survives a zone outage.
- C.GRS, because it adds a geographically replicated secondary region for disaster recovery.
- D.RA-GRS, because read access to the secondary region is the best protection against a zone failure.
Why B: B is correct because Zone-Redundant Storage (ZRS) synchronously replicates data across three Azure availability zones within the same region. This design ensures that if one datacenter or zone fails, the storage account remains available and durable without requiring a secondary region replica, exactly matching the business requirement.
Variation 2. A team stores application logs in an Azure Storage account. The logs must remain available if an entire Azure availability zone in the primary region has an outage, but the team does not require a secondary region copy. Which redundancy option should you choose?
easy- A.LRS
- ✓ B.ZRS
- C.GRS
- D.RA-GRS
Why B: Zone-redundant storage (ZRS) synchronously replicates data across three Azure availability zones within the primary region, ensuring durability even if an entire zone fails. Since the requirement explicitly states no secondary region copy is needed, ZRS is the correct choice because it provides intra-region zone-level resilience without cross-region replication.
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This AZ-104 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-104 exam.