Azure Functions Premium Plan maximum allowed scale out instances

Question

We currently using old cloud service classic which scale out to 100 instances.

We are interested to migrate to Azure Functions. Based on this doc, the best in terms of timeout and max instances is Premium Plan with timeout 30 minutes and max instances 100: https://docs.microsoft.com/en-us/azure/azure-functions/functions-scale#scale

But when i read this doc, it mentioned max instance is 20 only, so i am confuse: https://docs.microsoft.com/en-us/azure/azure-functions/functions-premium-plan?tabs=portal#always-ready-instances

Anyone has experience what's the max allowed scale out instance for Premium Plan? Thanks.

Answer 1

For premium plan, the pre-warmed instances can go up to 20; but total (or maxmium burst) can go up to 100.

When events begin to trigger the app, they are first routed to the always ready instances. As the function becomes active, additional instances will be warmed.