A very old joke, and in fact not much of a joke at all. But it does raise an interesting thought about Clouds and datacenters. When is a datacenter not a datacenter? When its a Cloud.
So what’s the difference? In a recent blog post, Don Macvittie from F5 said “The “Cloud” is someone else’s datacenter running your app. Yeah, it really is that simple. Software As A Service evolved”.
I was at CloudCamp London on the 9th of July where it was suggested that there were well over 60 definitions of Cloud Computing but at one point all the panellists did agree that the main difference between a virtualized datacenter and a cloud was the business model.
Coincidentally, all the panellists had been talking to financial institutions about Cloud Computing that day. Hopefully not the same one - I think there are more than just a few enterprises now actively investigating what Clouds could offer them so let’s hope they aren’t all pursuing the same opportunity.
Imagine a datacenter before virtualization but after you had moved it out from your basement (not too difficult as its recent history, but its history none the less). It was a mix of commodity and custom hardware doing commodity and custom things. Some good solutions were developed to perform specific tasks but how flexible was it? How quickly could you scale your infrastructure up and down?
Could an old fashioned physical datacenter have been a Cloud? No. Can a virtualized datacenter become a Cloud? Yes it can, because the attributes of a virtualized environment allow for the flexible ‘pay as you go’ business model that is now being seen as defining what a Cloud is. You can spin up another VM instance or order up more storage and pay for it as you use it. You can spin up software applications and software traffic management and spin them down just as easily. Your Cloud provider (public or private) can allocate his resources on demand in what is a multi-tenancy environment, with memory, CPU or other resources moved from customer to customer or dept to dept.
So Cloud Computing can take place where ever your virtual datacenter is, even if you have left it in the basement. But you need to ensure that all the functionality you want can fit into the new business model. Flexible software solutions sitting on commodity hardware will give you that.
Try spinning up a 45lb piece of custom hardware when you need it and then sticking it back in the box and returning it for a refund when you don’t need it anymore and you’ll see that there are some things that just aren’t ever going to be in a Cloud.
Nick Vale
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