- A
Azure Table Storage
Why wrong: Azure Table Storage is a NoSQL key-value store but does not support multi-region writes with automatic conflict resolution or serverless capacity. It also may not achieve single-digit millisecond latency at global scale.
- B
Azure Cosmos DB
Cosmos DB provides guaranteed single-digit millisecond latency, multi-region writes (multi-master), automatic conflict resolution, and a serverless mode that automatically scales capacity based on workload.
- C
Azure Cache for Redis
Why wrong: Azure Cache for Redis is an in-memory cache, not a durable database. It does not provide multi-region writes with conflict resolution or serverless capacity as a primary data store.
- D
Azure SQL Database
Why wrong: Azure SQL Database is a relational database, not a NoSQL key-value/document store. It does not natively support document models or multi-region writes with conflict resolution like Cosmos DB.
Quick Answer
The answer is Azure Cosmos DB, the fully managed NoSQL database that natively supports both key-value and document models while guaranteeing single-digit millisecond latency at any scale. This is correct because Cosmos DB’s multi-master replication enables multi-region writes with automatic conflict resolution, and its serverless capacity mode dynamically scales to handle unpredictable traffic without provisioning. On the AZ-305 exam, this scenario tests your ability to match workload requirements to the correct data service, often appearing as a distractor against alternatives like Azure Table Storage (key-value only) or Azure SQL Database (relational). A common trap is choosing Azure Table Storage for key-value needs, but it lacks document support and multi-region writes. Remember the memory tip: “Cosmos covers all—key, doc, multi-write, serverless call.”
AZ-305 Design data storage solutions Practice Question
This AZ-305 practice question tests your understanding of design data storage solutions. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A company needs a fully managed NoSQL database for a new application with a key-value and document data model. They require single-digit millisecond latency at any scale, multi-region writes with automatic conflict resolution, and a serverless capacity option to handle unpredictable traffic. Which Azure data service should they use?
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
Azure Cosmos DB
Azure Cosmos DB is the correct choice because it is a fully managed NoSQL database that supports both key-value and document data models natively. It guarantees single-digit millisecond latency at any scale, offers multi-region writes with automatic conflict resolution via its multi-master replication, and provides a serverless capacity mode that automatically scales based on demand, making it ideal for unpredictable traffic.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Azure Table Storage
Why it's wrong here
Azure Table Storage is a NoSQL key-value store but does not support multi-region writes with automatic conflict resolution or serverless capacity. It also may not achieve single-digit millisecond latency at global scale.
- ✓
Azure Cosmos DB
Why this is correct
Cosmos DB provides guaranteed single-digit millisecond latency, multi-region writes (multi-master), automatic conflict resolution, and a serverless mode that automatically scales capacity based on workload.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Azure Cache for Redis
Why it's wrong here
Azure Cache for Redis is an in-memory cache, not a durable database. It does not provide multi-region writes with conflict resolution or serverless capacity as a primary data store.
- ✗
Azure SQL Database
Why it's wrong here
Azure SQL Database is a relational database, not a NoSQL key-value/document store. It does not natively support document models or multi-region writes with conflict resolution like Cosmos DB.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often confuse Azure Table Storage as a NoSQL database that supports multi-region writes, but it lacks document support and automatic conflict resolution, making Cosmos DB the only option that meets all requirements.
Detailed technical explanation
How to think about this question
Under the hood, Azure Cosmos DB uses a multi-master replication protocol that allows any region to accept writes, with automatic conflict resolution using last-writer-wins (LWW) or custom conflict resolution policies. Its serverless mode uses a consumption-based billing model where you pay only for the request units (RUs) consumed, with no need to provision throughput upfront, and it automatically scales from 0 to 1000 RUs per second. A real-world scenario is a global e-commerce application that needs to handle flash sales with unpredictable spikes; Cosmos DB's serverless mode avoids over-provisioning while maintaining low latency across regions.
KKey Concepts to Remember
- Read the scenario before looking for a memorised answer.
- Find the constraint that changes the correct option.
- Eliminate answers that are true in general but not in this case.
TExam Day Tips
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A media company stores terabytes of video archives that are accessed once a year for audit purposes. Moving these objects to a cold storage tier (Azure Archive, S3 Glacier, or Google Nearline) costs a fraction of hot storage. Questions like this test whether you understand storage tiers, access frequency tradeoffs, and retrieval latency requirements.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
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Design data storage solutions — study guide chapter
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FAQ
Questions learners often ask
What does this AZ-305 question test?
Design data storage solutions — This question tests Design data storage solutions — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Azure Cosmos DB — Azure Cosmos DB is the correct choice because it is a fully managed NoSQL database that supports both key-value and document data models natively. It guarantees single-digit millisecond latency at any scale, offers multi-region writes with automatic conflict resolution via its multi-master replication, and provides a serverless capacity mode that automatically scales based on demand, making it ideal for unpredictable traffic.
What should I do if I get this AZ-305 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
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Last reviewed: Jun 11, 2026
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.
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