What instance type should I choose?

To run video chat service?

High开发者_如何学运维-Memory or High-CPU? And, guess Standard isn't suitable?

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.