Up in the air .... Is the private cloud is a mythical beast?
Cloud computing is a tricky enough concept to grasp but what about "private cloud" computing? Private clouds are often mentioned in the same breath as "public cloud", or worse, "hybrid cloud" yet some industry experts argue that there is no such thing.
So what are all those technology vendors going on about?
Confusion reigns but Dave Hanrahan, Dimension Data's general manager - cloud services, says there is a clear definition of true private cloud, and one his company and others adhere to in their offerings.
Hanrahan says all DiData's cloud services - public, private and hybrid - are aligned with formal definitions set out by the US (NIST).
According to NIST, to be called "cloud" a service must meet five critical IT characteristics: on-demand self-service, broad network access, resource pooling, rapid elasticity and measured service.
"They defined public being shared multi-tenant [servers and storage], private being [servers and storage] dedicated to one organisation and hybrid being services operated in either public or private, or a blend of the two."
So in basic terms, the difference is whether the virtualised machines are used by one client alone, or shared by more than one.
Private cloud is a mythical beast, says James O'Rourke, founder of boutique consultancy Cloud Advantage.
"Private clouds, for my money, are usually little more than virtualised server farms renamed to have the word cloud in the name," he wrote in a recent blog.
He suggests the term has been coined "just to give people a feeling that they too can have 'cloud' and be really modern even if they own all their own hardware with the related complications."
However, O'Rourke says the term is gaining currency which he attributes in part to hardware vendors and IT departments.
"I think a lot of the big hardware companies are pushing it ... to extract a much better margin."
He suggests hardware vendors do this by promoting "private cloud" solutions to enterprises on prices different to those paid by large public cloud providers such as Amazon, Google and Microsoft which demand huge cuts in hardware costs.
Giri Fox, director Asia Pacific of RightScale, a provider of cloud management services, agrees there is confusion around the meaning of "private cloud" and opts for a broad, pragmatic definition.
"For an enterprise that is trying to exploit cloud, it does not matter whether it is cloud in the most philosophical of definitions," he says.
Opex v Capex
The issue of capital expense or operating expense allocation is one often discussed in conjunction with the potential for cloud. As the theory goes, cloud computing allows companies to move the cost of buying IT infrastructure from a capital expense to paying for the maintenance of that infrastructure owned by others as an operational expense.
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