I’d like to celebrate the end of this series of cloud articles by summarising some of the issues we’ve covered previously, and by answering a few questions that are impossible to answer. Or at least, questions that fall into the “how long is a piece of string” category.

Given the nebulous perception most people have of the cloud, one common question is just how much kit do you need to get started?

If you outsource, of course, you don’t need infrastructure at all, which is a large part of the attraction of the cloud in the first place. Get rid of all that pesky hardware, and let your cloud provider worry about the nuts and bolts, the maintenance, replacement schedules, downtime, amortization and so on. You’ll still need end user devices, and the chances are you won’t be able abandon everything in your server room... but you’ll certainly be able to make an appreciable difference to the balance sheet in terms of infrastructure capex and running costs.

And if you’re building it yourself? That’s a string length question. It depends how big you build it, and to some extent on which platform you use. A typical ‘bare minimum’ cloud will usually have some kind of controller server; at least two hypervisors to host virtual machines (you could probably get away with one, but then you wouldn’t have the ability to failover, and wouldn’t really have a cloud); and of course, some storage and backup.

Storage is usually the single biggest hardware cost. High-end enterprise storage is eye-wateringly expensive. You can keep costs down by using commodity storage products, software SANs and the like, and there are a few cloud products on the horizon that promise to provide high performance cloud storage at low cost. Shop around!

Let’s assume you’re going down the outsourcing route. What sourcing options do you have, and how much does it cost? That also depends. We’ve already discussed the differences between building your own cloud, using the public cloud, or using a third party to provide you with your own private cloud. That should be governed by what you’re trying to do in the cloud and the associated benefit/risk assessment.

We have also considered some of the issues you should consider when choosing a cloud provider – their skills, knowledge of your business, SLAs, platform and application support, and so on. That just leaves the cost question. If you go with a third party provider, what can you expect to spend?

Back to the string, I’m afraid. There can be material differences between providers that explain why there are cloud services priced at $30 or $300 a month. These things can be determined by the power of the hardware, the speed of the storage and the quality of the datacenter, for example.

Overall, though, the trend (indeed the whole point) of something-as-a-service in the cloud is towards commoditisation of IT resources, especially at the infrastructure level. In the end, you’re just buying compute cycles and disk space, and that stuff is basically the same wherever you buy it.

What that means is the real differences between cloud providers are to be found in the value-added services they provide – the apps on offer, the support included, the response time for fixes and compensation for outages. Once you’re satisfied from a technology standpoint, these things should drive your decision-making process.

I suppose all this talk of string might feel like a cop-out, so as kind of compensation I’d like to finish with a string metaphor that may actually be of some use.

While there are people who still foam at the mouth at the prospect of being ‘in the cloud’, the reality for most businesses is, well, reality: IT costs and ROI. Uptime and maintenance. Ease of use and the customer experience.

So if the cloud really were a piece of string, you’d just want make sure it’s elastic enough to go round the app, process, department or company you want to cloud-enable. You’d make sure it’s the right kind of string for your end users – not too rough around the edges, or too inflexible for the things your IT department needs it to do. You’d make sure it’s the kind of string that fits with your budget, billing, compliance and security requirements.

Above all, you’d make sure it’s strong enough not to break, and that if it does break, your provider would be obliged to fix it PDQ. Good luck!