AZ-305 Design data storage solutions Practice Question
Your company needs to store configuration data (key-value pairs) for applications in a highly scalable and low-latency manner. The data is accessed frequently. Which Azure service should you choose?
⚠ Common exam trap
Test-takers frequently confuse Azure Cache for Redis with Azure Cosmos DB or Azure Table Storage, assuming any key-value store is equivalent, but the exam emphasizes the specific requirement for 'highly scalable and low-latency' access, which only an in-memory cache like Redis can deliver for frequently read configuration data.
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 Cache for Redis.
Azure Cache for Redis is the correct choice because it provides an in-memory data store that delivers extremely low-latency access (typically sub-millisecond) and high throughput for frequently accessed key-value configuration data. It supports common data structures like strings, hashes, and lists, and can be used as a distributed cache or session store, making it ideal for high-frequency read workloads where persistence is not the primary concern.
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 it's wrong here
Azure Cosmos DB is a globally distributed NoSQL database designed for multi-model data with complex querying and transactional guarantees, not a dedicated configuration store. The scenario requires a low-latency, highly scalable key-value store for frequently accessed configuration data, which Azure App Configuration provides natively with managed endpoints and automatic caching. Cosmos DB is tempting because it offers low latency and scalability, but it introduces unnecessary cost and operational overhead for simple key-value lookups, where App Configuration’s purpose-built service avoids provisioning throughput and index management.
- ✓
Azure Cache for Redis.
Why this is correct
Azure Cache for Redis is a managed in-memory data store that delivers sub-millisecond read latency and native support for key-value pairs, making it ideal for frequently accessed configuration data. Unlike disk-backed services, it holds the working set entirely in RAM, and its automatic scaling and built-in data expiration policies simplify lifecycle management. For simple get/set lookups, this purpose-built caching tier minimizes both latency and operational overhead compared to general-purpose databases.
- ✗
Azure SQL Database.
Why it's wrong here
Azure SQL Database is a fully managed relational database engine that persists data on durable, page-compressed storage and enforces ACID transactions and a fixed schema. The cost of TCP connection setup, protocol parsing, and query optimization adds meaningful latency for each lookup, especially for simple key-value accesses that do not need joins or aggregates. While it can store configuration rows, its disk-backed architecture and relational overhead make it an unnecessarily slow and expensive choice compared to an in-memory cache for this low-latency use case.
- ✗
Azure Table Storage.
Why it's wrong here
Azure Table Storage is a non-relational key-value service that scales massively, but it is backed by Azure Blob Storage and each query incurs network and disk I/O, typically in the single-digit-millisecond to tens-of-milliseconds range. It offers no built-in TTL or advanced data structures like Redis sorted sets, so developers must manually manage configuration refreshes and eviction. For hot configuration data accessed on every request, this latency and lack of caching semantics make it inferior to an in-memory option like Azure Cache for Redis.
Go deeper
Related to this question
About these practice questions
One of 795 original AZ-305 practice questions on Courseiva, each with a full explanation and wrong-answer analysis — not exam dumps or protected exam content. Learn why practice questions differ from exam dumps →
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.