When we should create Functions under same Function App and when should not

Question

Hello !!! I have a question regarding Azure Function !!!

So I have 3 Azure Functions. They are doing the following:

1. Event Hub trigger
2. Time trigger syncing some cache data of the MongoDB database and Redis
3. Another Time trigger doing some schedule checking.

Should I create them under a Single Function App or create 3 different Function App? If I create them under one function app, then are they going to have any scalability issue?

When we should create Functions under same Function App and when should not?

Answer 1

The functions you mentioned can be placed inside the same function app and I don't see any scalability issues.

Regarding your question: multiple Function Apps or one Function App with multiple functions, I don't think there is an exact guideline on how to design your functions. Saying that Function Apps uses a storage account to maintain its operations such as managing triggers and logging function executions etc. All the functions inside the Function App share that storage account. Say, you have a Durable Function, it's heavily using the storage account, so it's best to isolate that with a different Function App.

These might help,
Optimize the performance and reliability of Azure Functions
Azure Functions scale and hosting