Wednesday, 26 September 2007

On Demand versus virtualization

You might very well think this is a strange title for a blog – after all, they seem like two completely different things. It’s like saying apples versus mountain bikes!

However, think about it a little deeper. Both of them are trends in computing and both would take IT departments in totally different directions. At some stage, managers are going to have sit down and decide which route they are going to take.

Let me explain my thinking in more detail.

On Demand computing describes a method of making computing resources available to users at the time those resources are needed. Basically what happens is this: users have lots of computer capacity available at their site, but pay only for the capacity they use. That way they are not paying to support peak capacity during quieter periods. They use as much capacity as they require at any one time and that’s all they pay for. They don’t pay for the extra capacity on the occasions when it isn’t needed, only when it is needed and used. On Demand computing has been tipped by many to be the next big trend in computing. After all, it makes sense for a company to have all the capacity it will ever need, but only pay for the capacity it is actually using.

Virtualization, on the other hand, is a technique that allows users to maximize the use they get from their existing hardware. You don’t need more, you just utilize what you already have better. Virtualization techniques allow hardware to “appear” to be available to users. It can even make non-existent devices appear to be available. It then takes the call to that device and routes it somewhere else – all completely seamlessly to the user. However, the important point in this debate is that it maximizes the usage of the hardware that is installed. Mainframers are familiar with VM, PR/SM and all the other virtualization techniques that have been around for many years. AIX users are now able to benefit from virtualization and so are System i users and even sites with x86 servers.

The advantages of choosing the virtualization route are that virtualization will reduce the amount of hardware that needs to be switched on, and so will reduce electricity bills. On Demand requires that data centres have the hardware delivered and installed. Not having it delivered will save petrol and will be a component of a company’s “green” strategy. Companies will also need less air conditioning (and again less electricity) because they won’t have to cool these extra boxes.

The one big thing in favour of On Demand computing is that it is an easier strategy. The extra boxes are used when needed and money is paid out at the end of the month (or whatever the charging period is). With virtualization you need to buy the software and have someone who knows what they’re doing to install it. You then need expertise to set up and run the virtual machines.

What I am suggesting is that when IT departments sit down to decide where they want to be in five years time and how they can achieve those goals. they will prefer to develop their own expertise in virtualization and be able to take all the advantages this will offer both now and in the future rather than install extra just-in-case capacity.
What do you think?

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