AZ-305 Design data storage solutions Practice Question
A company is designing a data storage solution for its IoT devices that generate telemetry data. The data is ingested at high velocity (millions of events per second) and must be stored for real-time dashboards and historical analysis. The solution must also support complex event processing and alerting. Which two Azure services should the company use together? (Choose two.)
⚠ Common exam trap
Watch out — candidates often confuse Azure IoT Hub with Event Hubs, assuming IoT Hub is the default for all IoT data ingestion, but IoT Hub is for device management and lower-throughput scenarios, while Event Hubs is the correct choice for high-velocity, multi-million-events-per-second telemetry ingestion.
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 Event Hubs
Azure Event Hubs is the correct choice because it is a high-throughput data ingestion service designed to handle millions of events per second from IoT devices, providing low-latency, durable event capture for real-time dashboards and historical analysis. Azure Stream Analytics is the correct companion service because it natively integrates with Event Hubs to perform complex event processing (CEP), such as pattern matching, aggregation, and alerting, on the streaming telemetry data in real time.
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 IoT Hub
Why it's wrong here
Azure IoT Hub is optimized for device connectivity, identity/authentication, and bidirectional command/control (device twins, direct methods), not for telemetry-scale data storage. Its built-in telemetry forwarding relies on an Event Hubs-compatible endpoint, but the service's per-device management overhead and throughput limits make it the wrong choice as the dedicated high-throughput ingestion layer for a data storage solution.
- ✓
Azure Event Hubs
Why this is correct
Azure Event Hubs is the correct choice because it is a fully managed, partitioned event-streaming platform engineered for high-throughput telemetry ingestion from millions of IoT devices, supporting millions of events per second and automatic data retention for replay. It decouples producers (devices) from consumers, exposes Kafka-compatible APIs, and enables Stream Analytics, functions, or custom consumers to process the stream, making it the foundational buffer before durable storage.
- ✓
Azure Stream Analytics
Why this is correct
Azure Stream Analytics is a serverless real-time analytics service that runs continuous SQL-like queries over streaming data, performing filtering, aggregation, windowing, and alerting. While it is a valid part of an IoT data pipeline, it operates as a processing layer downstream of an ingestion service such as Event Hubs; it does not itself provide durable, high-volume event storage or the ingestion endpoint that the IoT devices would send messages to.
- ✗
Azure Synapse Analytics
Why it's wrong here
Azure Synapse Analytics is an enterprise data warehousing and analytics platform with dedicated SQL pools that excel at complex, high-latency queries over large, shared tables. It is not built for real-time event ingestion or per-message streaming; using it to receive IoT device telemetry directly would introduce significant latency and cost, so it belongs later in the pipeline as a serving/analytics layer after processing and storage.
- ✗
Azure Data Lake Storage Gen2
Why it's wrong here
Azure Data Lake Storage Gen2 is a massively scalable object store with a hierarchical namespace, ideal for landing raw files and historical IoT data in open formats like Parquet. However, it is purely a storage target and lacks any native event-ingestion, partitioning, or stream-processing capabilities; it should act as a sink for data after Event Hubs and Stream Analytics have ingested and processed it, not as the real-time data storage solution.
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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.