What instance type should I choose?

Question

To run video chat service?

High-Memory or High-CPU? And, guess Standard isn't suitable?

Answer 1

With EC2, it is incredibly easy to switch instances. What you really need is evidence of how exactly this service will use your hardware.

Start with the High-CPU, setup the software, create an EBS-based image, and then do some load testing. While the testing is running, take a look at the hardware activity. In Linux you can run "top" from the command line, I'm sure there is something in Windows that will do the same thing.

Take a look at CPU usage vs. Memory usage. If you see that you are running out of Memory while your CPU is still at 30% then launch a High-Memory instance from the image you created.

I've used this process on a standard Linux Apache PHP (no mysql) server, and hit it with 1000 simultaneous users via Apaches AB testing software across several laptops. I noticed that memory peaked while the CPU never ran over 35%, therefore I determined I needed more memory, and I suspect the same might be true in this case if your software spawns a worker instance for each connection.