503 error on azure cloud service

Question

We use Azure and have problems with our Cloud Service last two days. We get 503 error on site. It looks like one of web-roles reboots sometimes. But in dashboard all of them works fine. Application Insight and Logs doesn't show any problems. CPU, Memory, Exception rate - all OK.

But I found one interesting moment. SQL queries average time grew to 5 seconds. But I checked it on database, it worked normal. This means that 5 seconds is not execution time but connection. It looks too much for trace inside data center.

Does anyone have any ideas how I can find a solution of this problem?

Answer 1

When your app generates a lot of exceptions in short time IIS stops application pool and you get 503 error. For more details google for "IIS Rapid Protection".