DP-203 Design and implement data storage Practice Question
You are tasked with designing a data storage solution for a social media analytics company. They need to store user profile data (JSON) and social media posts (text and images). The data is used for machine learning models that require fast random access to individual user profiles and the ability to run analytical queries over posts. The solution must provide low-latency reads for user profiles (milliseconds) and support for large-scale analytics on posts. Which combination of Azure data services should you recommend?
⚠ Common exam trap
Many exam-takers choose Azure Cosmos DB for both workloads (Option B) because they assume its multi-model support handles analytics, but they overlook that Cosmos DB is a transactional database not designed for large-scale analytical queries, while ADLS Gen2 is purpose-built for data lakes and analytics.
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 for user profiles and Azure Data Lake Storage Gen2 for posts
Azure Cosmos DB provides low-latency (millisecond) reads for user profiles via its indexing and partitioning capabilities, ideal for fast random access. Azure Data Lake Storage Gen2 (ADLS Gen2) combines a hierarchical namespace with Blob Storage, enabling large-scale analytical queries on posts using tools like Azure Synapse Analytics or Spark, while efficiently storing text and images.
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 for user profiles and Azure Data Lake Storage Gen2 for posts
Why this is correct
Cosmos DB delivers single-digit-millisecond point reads for JSON profiles through its partitioned, indexed document store, meeting the low-latency requirement. Data Lake Storage Gen2 provides hierarchical namespace and massively parallel analytical engines for large-scale post analytics, satisfying the second half of the workload.
- ✗
Azure Cosmos DB for both user profiles and posts
Why it's wrong here
Cosmos DB delivers millisecond point reads for profiles, yet its analytical store and Synapse Link are not the intended engine for large-scale analytical queries over posts, which Azure Synapse Analytics handles. It is tempting because Cosmos DB is the standard choice for low-latency JSON document access at global scale.
- ✗
Azure SQL Database for both user profiles and posts
Why it's wrong here
Azure SQL Database stores JSON in columns but cannot meet millisecond random-access profile reads at social-media scale, and it is not the analytical platform for large-scale post queries. It is tempting as a familiar relational store, and would be correct for transactional workloads needing joins and strong consistency.
- ✗
Azure Table Storage for user profiles and Azure Blob Storage for posts
Why it's wrong here
Table Storage serves key-based profile lookups but cannot run analytical queries over posts, and Blob Storage offers no query engine for large-scale analytics. It is tempting as a cheap, high-throughput pairing, and would be correct if posts only needed durable object storage with no analytical querying requirement.
Go deeper
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Key term
Azure Synapse Analytics
Azure Synapse Analytics is a cloud-based data integration, warehousing, and analytics service that brings together big data and data warehouse capabilities under one platform.
Key term
Azure Data Lake Gen2
Azure Data Lake Gen2 is a cloud-based data storage service that combines the scalability and performance of a data lake with the hierarchical file system and security of a data warehouse, designed for big data analytics.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This DP-203 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 DP-203 exam.