The performance of application reduced drastically after implementing App Gateway

Question

Hi,

I have an application gateway with tier WAF V2, Capacity type: Manual, Instance count: 2, it has 2 backend app services.

Earlier when I was using directly the app services url to access the applications it was working faster, but after integration of application gateway before the app services the performance of the application has reduced drastically, and many times it gives error 504 Gateway time out.

The configuration of custom health probe is:

protocol: HTTPS

path: /

interval seconds: 30

timeout seconds: 300

unhealthy threshold: 3

http response status code match: 200-399, 404  

Answer 1

Enabling WAF does indeed impair the performance of your application.

I suggest that you leverage telemetry (such as Azure App Insights) to measure the end to end latency. Once you have gathered sufficient data you can share that here, and we can comment if it is out of the expected range.