Okay.. it’s been a while now and Cloud Computing is not that new. SaaS model is quite popular, but I’m still being asked what IaaS (Infrastructure as a Service) is about. I came up with an analogy to water which seems to be easy to understand. So how is IT similar to water? Let’s take a look at 3 different “levels” of IT infrastructure:

1. Shared Hosting – you have access to a big water container. So do other people. Actually – you share it with tens or even hundreds of other people. Because of that there are some very strict limitations. Obviously there are limits of how much water you can use. Sometimes there are also some limits on HOW you use it. You have no way of changing water’s clearance level, mineral composition, etc. You just get what they give you. But it’s cheap.

2. Dedicated Server – you’ve built your own well. It took you a while to get everything agreed with your providers but it’s finally here. Now only you use its resources. Actually – I bet there are way more resources then you need or will need. You’ll probably be using 15-20% of what you have, but you’ve paid the full price anyway! Or you’re paying it every month if you’ve rented your well from 3rd party. All resources are yours and you can use it the way you like. Unfortunately you also need to maintain your well, monitor it, make sure it works fine, etc. You’re also responsible for the “hardware” of your well. You can of course outsource that, but it’ll cost you extra and you still won’t have access to water when something goes wrong. If you run out of resources you’ll need to make your well deeper or build another one. Both ways it will be expensive, it’ll take you a while and you won’t be able to roll back if your water requirement decrease.

3. Cloud Computing – you’ve replaced your well with.. water tap. You still have 100% control on what you do with the water and how you do it – but access to the water is way simpler now. All you need to do is open the tap and it’s there for you immediately. When you need more – just open it wider. You can also close the tap when you don’t need water any more. Your usage is being monitored and you only pay for what you’ve used. Maintenance? Of course there’s a HUGE infrastructure behind your tap – network of waterworks getting water from various sources, filters, etc, but you really DON’T need to worry about that. All you care about is the tap which delivers what you need and when you need.