- A
Azure Cosmos DB
Correct. Azure Cosmos DB is a globally distributed, multi-model database service that natively supports multi-region writes (multi-master). It automatically replicates data across regions and provides guaranteed low latency for both reads and writes.
- B
Azure SQL Database
Why wrong: Incorrect. Azure SQL Database supports active geo-replication but only allows writes to a single primary region. It does not support simultaneous writes from multiple regions with automatic conflict resolution.
- C
Azure Database for PostgreSQL
Why wrong: Incorrect. Azure Database for PostgreSQL does not support multi-region writes. It can be configured with read replicas in other regions, but all writes must go to the primary server.
- D
Azure Cache for Redis
Why wrong: Incorrect. Azure Cache for Redis is an in-memory data store used for caching, not a durable database. It does not provide multi-region write capabilities with automatic conflict resolution.
Quick Answer
Azure Cosmos DB is the correct choice because it is the only Azure database service that natively supports multi-region writes with low latency, meeting the exact needs of a globally distributed application. This fully managed NoSQL database automatically replicates data across any number of Azure regions, guaranteeing single-digit millisecond latency for both reads and writes at the 99th percentile, and it includes built-in conflict resolution policies like last-writer-wins to handle simultaneous updates from different regions. On the AZ-900 exam, this question tests your understanding of which service solves the specific scenario of global, low-latency, multi-region writes—a common trap is confusing Azure SQL Database (which requires manual configuration for geo-replication and does not natively support multi-region writes) with Cosmos DB. Remember the key phrase: if the scenario demands native multi-region writes and single-digit millisecond latency, think Cosmos DB. A helpful memory tip is to associate “Cosmos” with “cosmic scale” and “global distribution,” and to recall that Cosmos DB is the only service that offers a multi-region write capability out of the box.
AZ-900 Describe Azure architecture and services Practice Question
This AZ-900 practice question tests your understanding of describe azure architecture and services. 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 global e-commerce company needs to store product catalog data that must be available for reads and writes from multiple Azure regions simultaneously. The application requires consistently low latency (single-digit milliseconds) for writes from any region, and the database must automatically replicate all changes across regions with conflict resolution. The company wants a fully managed database service with native multi-region write support. Which Azure database service should the company 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 service that natively supports multi-region writes with automatic and synchronous replication across any number of Azure regions. It guarantees single-digit millisecond latency for reads and writes at the 99th percentile, and provides built-in conflict resolution policies (e.g., last-writer-wins or custom) to handle concurrent updates from different regions. This makes it ideal for globally distributed applications requiring consistent low-latency writes and automatic replication.
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 Cosmos DB
Why this is correct
Correct. Azure Cosmos DB is a globally distributed, multi-model database service that natively supports multi-region writes (multi-master). It automatically replicates data across regions and provides guaranteed low latency for both reads and writes.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Azure SQL Database
Why it's wrong here
Incorrect. Azure SQL Database supports active geo-replication but only allows writes to a single primary region. It does not support simultaneous writes from multiple regions with automatic conflict resolution.
- ✗
Azure Database for PostgreSQL
Why it's wrong here
Incorrect. Azure Database for PostgreSQL does not support multi-region writes. It can be configured with read replicas in other regions, but all writes must go to the primary server.
- ✗
Azure Cache for Redis
Why it's wrong here
Incorrect. Azure Cache for Redis is an in-memory data store used for caching, not a durable database. It does not provide multi-region write capabilities with automatic conflict resolution.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often confuse Azure SQL Database's active geo-replication or failover groups with true multi-region write support, but those features only allow reads from replicas and require a single write region, whereas Cosmos DB is the only service that natively handles concurrent writes from multiple regions with automatic conflict resolution.
Detailed technical explanation
How to think about this question
Azure Cosmos DB achieves multi-region writes through its multi-master replication protocol, which uses a consensus-based approach (e.g., with session, consistent prefix, or eventual consistency levels) to ensure that writes are accepted in any region and asynchronously replicated. The service offers multiple consistency models, and for multi-region writes, the default is eventual consistency unless you configure a stronger model, which may impact write latency. In a real-world scenario, a global e-commerce catalog would use Cosmos DB's multi-master with last-writer-wins conflict resolution to ensure that price or inventory updates from any region are automatically reconciled without data loss.
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 cloud solutions architect for a retail company is evaluating services for a new workload. The correct answer here reflects best practice for the specific scenario described — not a general cloud recommendation. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Cloud exam questions reward reading the constraint carefully: the same technology can be right or wrong depending on the use case.
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.
- →
Describe Azure architecture and services — study guide chapter
Learn the concepts, then practise the questions
- →
Describe Azure architecture and services practice questions
Targeted practice on this topic area only
- →
All AZ-900 questions
1,031 questions across all exam domains
- →
Microsoft Azure Fundamentals AZ-900 study guide
Full concept coverage aligned to exam objectives
- →
AZ-900 practice test guide
How to use practice tests most effectively before exam day
Related practice questions
Related AZ-900 practice-question pages
Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.
Describe cloud concepts practice questions
Practise AZ-900 questions linked to Describe cloud concepts.
Describe Azure architecture and services practice questions
Practise AZ-900 questions linked to Describe Azure architecture and services.
Describe Azure management and governance practice questions
Practise AZ-900 questions linked to Describe Azure management and governance.
AZ-900 Azure services practice questions
Practise AZ-900 questions linked to AZ-900 Azure services.
AZ-900 pricing and support practice questions
Practise AZ-900 questions linked to AZ-900 pricing and support.
AZ-900 security and compliance practice questions
Practise AZ-900 questions linked to AZ-900 security and compliance.
AZ-900 governance practice questions
Practise AZ-900 questions linked to AZ-900 governance.
Practice this exam
Start a free AZ-900 practice session
Short sessions build daily habit. Longer sessions build exam-day stamina. Try a timed session to simulate real conditions.
FAQ
Questions learners often ask
What does this AZ-900 question test?
Describe Azure architecture and services — This question tests Describe Azure architecture and services — 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 service that natively supports multi-region writes with automatic and synchronous replication across any number of Azure regions. It guarantees single-digit millisecond latency for reads and writes at the 99th percentile, and provides built-in conflict resolution policies (e.g., last-writer-wins or custom) to handle concurrent updates from different regions. This makes it ideal for globally distributed applications requiring consistent low-latency writes and automatic replication.
What should I do if I get this AZ-900 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
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Last reviewed: Jun 11, 2026
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.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.