Azure IOT Hub scaling options & EventHub?

Hello Anirudh Singh Bharti,

Welcome to Microsoft Q&A and Thank you for reaching out.

I understand that you want to know about the scaling options available for Azure IoT Hub and how to implement auto-scaling for both IoT Hub and Event Hub. Here’s some detailed information that might help you out

Azure IoT Hub – Scaling Options

Azure IoT Hub provides multiple mechanisms to scale based on message volume, throughput needs, and number of connected devices. The primary way to scale IoT Hub is by increasing the number of units or upgrading to a higher SKU. Each SKU comes with a fixed daily message allowance:

S1: ~400,000 msgs/day per unit

S2: ~6 million msgs/day per unit

S3: ~300 million msgs/day per unit

Increasing the number of units or changing to a larger SKU increases your message capacity and overall throughput. In addition, IoT Hub uses partitions to handle device-to-cloud messages in parallel. More partitions support higher concurrency, though the partition count must be selected during creation and cannot be changed later.

Vertical & Horizontal Scaling

IoT Hub supports:

Vertical scaling: Upgrade from S1 → S2 → S3 or add more units.

Horizontal scaling: Deploy additional IoT Hub instances and distribute device workloads across them.

Routing auto-scaling: All internal routing features automatically scale to handle load without any configuration from your side.

These options together ensure that IoT Hub can handle growth across both throughput and device count.

IoT Hub Auto-Scaling (Not Native)

IoT Hub does not support built-in auto-scaling. However, customers typically achieve automated scaling using Azure Monitor and Azure Automation. You can monitor metrics such as:

Incoming messages vs quota

Throttled requests

Device-to-cloud send failures

With alerts triggering an Automation Runbook or Logic App, the system can automatically increase or decrease IoT Hub units through ARM or REST API calls. This approach gives you automated scaling behavior, even though it is not native to the IoT Hub service.

Azure Event Hubs – Scaling Options

Azure Event Hubs is designed for high-throughput real-time ingestion and offers flexible scaling.

Event Hubs can scale through:

• Throughput Units (Standard tier):
  • 1 MB/s ingress per TU
  • 2 MB/s egress per TU
• Processing Units (Premium tier):
  • Dedicated resources and predictable performance
• Partitions:
  • More partitions increase parallel processing capability
  • Partition count must be defined at creation

These scaling mechanisms allow Event Hubs to handle millions of events per second when configured correctly.

Event Hubs Auto-Scaling (Native)

Unlike IoT Hub, Event Hubs supports native auto-scaling via Auto-Inflate.

When Auto-Inflate is enabled:

Event Hub automatically increases Throughput Units

Scaling is based on ingestion load

You define the maximum TU limit

This ensures seamless handling of traffic spikes without manual intervention.

Please refer this

• Azure IoT Hub pricing and scaling
• IoT Hub Autoscaling Sample
• Event Hubs Quotas and Limits

I Hope this helps. Do let me know if you have any further queries.

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Thank you!