Taking Amazon EC2 as an example… its sounds pretty simple to begin with…
Pay only for what you use. There is no minimum fee. Estimate your monthly bill using AWS Simple Monthly Calculator. The prices listed are based on the Region in which your instance is running. For a detailed comparison between On-Demand Instances, Reserved Instances and Spot Instances, see Amazon EC2 Instance Purchasing Options.
But read on, and you discover you can choose between ‘free tier’ or ’on-demand’ or ‘reserved instances’ both with different pricing models, and you can even bid to buy unused capacity in the shape of a ‘spot instance’. You’re maybe thinking that when you’ve worked this all out then you’re done… not quite. On top of this you then incur data transfer charges, elastic load balancing and Amazon S3 block storage charges.
I wonder how many people pick something small and simply put their credit card details in hoping the bill at the end of the month won’t be too bad?
Well, a word of advice… If you’re running a small application periodically (and remember to shut it down, because you’ll still be charged if you leave the lights on) then you’ll be amazed how little this costs. However, if you’re running a decent sized business application 24×7 then you’ll be amazed how much the costs mount up… and you might even resort to searching for the chap who told you that cloud was cheaper than owning your own hardware.
To compare and contrast let’s have a look how Microsoft promote Azure, again pretty simple on the surface:
You have two basic types of offers to choose from when purchasing a Windows Azure platform subscription. The first type is consumption offers. This type requires no commitment – you pay only for what you use. The second type of offer is a commitment offer that provides a significantly discounted level of service in return for a six month commitment to pay a monthly base fee. Any usage in excess of this amount is charged at our standard consumption rates. Here is a summary of our different plans:
There is also a MSDN Premium license for developers, but like Amazon when you get into the detail it can be complex. What’s more they offer packages in the shape of a Development Accelerator Core a Development Accelerator Extended and a SQL Azure Development Accelerator Core … Fantastic… erm no… this is confusing for a seasoned IT person. I wonder what a small or medium sized business looking to move some systems to the cloud would make of it.
Rackspace are another one of the ‘big cloud players’ and their proposition seems much easier to understand on the surface:
You pay for each Cloud Server (virtual instance) by the hour. For your convenience, the monthly totals are also listed here.
However, on top of the basic instance you again have to pay for data transfer costs and also you need to pay for cloud files storage (similar to Amazon S3) and the cost varies depending if you run a Linux or the more expensive Windows OS.
Amazon, Microsoft and Rackspace, although big names, are only a small sample of dozens of cloud providers operating today… have a look at www.cloudpricecalculator.com to see some of the others.
The cloud is for everyone, but not for everything…