Hi all,
since we just stumbled over a very high webserver load during the start of the semester on one of our platforms (ILIAS 8) I want to make sure that you are aware of this issue: If the notifications in "Administration -> Communication -> Notifications" are enabled please make sure that your "Refreshinterval" is big enough (a recommended value would be 60000 (which is 60s in ms)). Otherwise you might receive a kind of ddos by your users' browsers if the notifications route is not rate limited :-)
I hope that will help someone. Thanks @mjansen for the hint.
Best regards, Rob