Question 309 of 999
Design data storage solutionshardMultiple ChoiceObjective-mapped

Quick Answer

The answer is Azure Cosmos DB with multi-master and per-request consistency override. This configuration is correct because multi-master enables low-latency multi-region writes for global IoT telemetry ingestion, while automatically handling concurrent document updates through last-writer-wins or custom conflict resolvers. The per-request consistency override then allows the application to demand strong consistency for critical device command reads, yet fall back to eventual consistency for user-facing dashboard queries, perfectly balancing performance and data integrity. On the AZ-305 exam, this scenario tests your understanding of how to combine global write distribution with granular consistency control, a common trap being to assume a single consistency level must apply to all operations. Remember the memory tip: “Multi-master for writes, per-request for reads” — strong for commands, eventual for dashboards.

AZ-305 Design data storage solutions Practice Question

This AZ-305 practice question tests your understanding of design data storage solutions. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. 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 IoT platform ingests telemetry data from millions of devices. The application requires multi-region writes to support low-latency ingestion from any location. The schema uses JSON documents and fields often vary. The team needs automatic conflict resolution when the same document is updated concurrently from different regions. Additionally, read operations for device commands must use strong consistency, while user-facing dashboard queries can use eventual consistency. Which Azure Cosmos DB configuration should they choose?

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 with multi-master and per-request consistency override

Option C is correct because the scenario requires multi-region writes (multi-master) for low-latency ingestion, automatic conflict resolution (which multi-master provides via last-writer-wins or custom conflict resolvers), and strong consistency for device command reads while allowing eventual consistency for dashboards. Per-request consistency override in Azure Cosmos DB lets the application set strong consistency on specific read operations (e.g., device commands) while defaulting to eventual consistency for others, meeting all requirements without sacrificing performance.

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 with single-master and multiple read regions

    Why it's wrong here

    Single-master allows writes only in one region, so multi-region writes are not possible. This does not meet the low-latency ingestion requirement from all regions.

  • Azure Cosmos DB with multi-master and default strong consistency

    Why it's wrong here

    While multi-master supports multi-region writes, default strong consistency would cause higher write latency due to synchronous replication across regions, which may not be optimal for all operations.

  • Azure Cosmos DB with multi-master and per-request consistency override

    Why this is correct

    Multi-master allows writes in any region and automatic conflict resolution. Per-request consistency override enables the application to use strong consistency for critical device command reads and eventual consistency for other reads, meeting all requirements.

    Related concept

    Read the scenario before looking for a memorised answer.

  • Azure Cosmos DB with multi-master and eventual consistency only

    Why it's wrong here

    Eventual consistency only cannot guarantee strong consistency for device command reads, which is required.

Common exam traps

Common exam trap: answer the scenario, not the keyword

The trap here is that candidates often assume multi-master forces a single consistency level across all operations, but Azure Cosmos DB allows per-request overrides to mix consistency levels, which is the key to satisfying mixed requirements without over-provisioning.

Trap categories for this question

  • Command / output trap

    Eventual consistency only cannot guarantee strong consistency for device command reads, which is required.

Detailed technical explanation

How to think about this question

Azure Cosmos DB multi-master uses a last-writer-wins (LWW) conflict resolution policy by default, which automatically resolves concurrent updates based on a timestamp or custom property. The per-request consistency override is implemented via the `x-ms-consistency-level` header in the REST API or the `ConsistencyLevel` property in the SDK, allowing a single request to use strong consistency while the account defaults to eventual. This is critical for IoT scenarios where device commands must be read with absolute freshness, but dashboards can tolerate stale data to reduce latency.

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.

Related practice questions

Related AZ-305 practice-question pages

Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.

Practice this exam

Start a free AZ-305 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-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 with multi-master and per-request consistency override — Option C is correct because the scenario requires multi-region writes (multi-master) for low-latency ingestion, automatic conflict resolution (which multi-master provides via last-writer-wins or custom conflict resolvers), and strong consistency for device command reads while allowing eventual consistency for dashboards. Per-request consistency override in Azure Cosmos DB lets the application set strong consistency on specific read operations (e.g., device commands) while defaulting to eventual consistency for others, meeting all requirements without sacrificing performance.

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

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 →

How Courseiva writes practice questions · Editorial policy

Keep practising

More AZ-305 practice questions

Last reviewed: Jun 11, 2026

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.

Loading comments…

Sign in to join the discussion.

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.