I know this question is vague, so if someone can share their stories like when they started out, what was their setup and what was the point when they had to think about scaling up.<p>I have an RoR app which I am about to launch in beta. The response time/load time is somewhere between 50ms to 300ms(fluctuating). I would like to know how soon I might have to think about scaling up(hardware).<p>Is going for dedicated hardware initially a good idea? My guess is that will reduce the load time further.
I've run production sites with thousands of users on a $20 VPS, but it very much depends on your app and what it does. There is no simple answer to this. I think the easiest way you can get some idea is a load test - ab for a simple test, and then perhaps httpperf or jmeter for simulated user tests. I wouldn't spend too long on it unless you are expecting very high traffic initially, but it can help you understand where your site bottlenecks are and what you will need to keep an eye on.<p>Also, since you are running RoR, make sure you have New Relic up and running to get early warning of issues!
I think you should optimize your code first. Are you sure the response time issues are a result of slow hardware?<p>Better hardware should always be one of the last things to consider. Maximize performance with what you have now and then consider alternatives if necessary.