The Azure Functions premium plan was created to overcome the limits of the consumption plan and app service plan.
With the Azure Functions premium plan, you pay per core seconds, execution time, and memory used across various instances. Premium plans have reserved instances that are warmed before use to avoid cold starts, and you will also pay for these.
Here are the main features of the premium plan:
- VNet connectivity and Visual Studio Live Debugging
- Unlimited execution duration
- Faster scale up and scale down than the app service plan
- No cold start time
Since plan features and limitations change over time, it's better to refer to the official documentation to see the actual values and current differences between various plans. This documentation can be found at https://docs.microsoft.com/en-us/azure/azure-functions/functions-scale.