In vertical scaling, we can increase the internal space based on the capacity of the instance right? we can do beyond the limit of instance right? please correct me if my understanding is wrong..

Could you help me understand in which situations we should go for vertical scaling and when horizontal scaling is the better choice?

Please provide the definition for hypervisor or explain this term

Is there any platform or application which we are using to create a sample web pages to test the IIS configuration

Please let me know the full form of .pem