The private cloud is not the same thing as a data center

Yes, there is such a thing as a private cloud. No, it’s not the same thing as having lots of virtual machines on your data center’s servers.

It’s the beginning of a new year, and I’ve already had someone ask me why they should bother with a private cloud when they already had lots and lots of virtual machines (VM)s in their data center.

Excuse me as I bang my head against the wall.

Guys, guys, if a cloud was just a bunch of servers, virtual or otherwise, we’d still be stuck in the ’90s. Oh, that’s right. Some of you still are.

OK, I’ll make it simple. Flip open your copy of the National Institute and Technology’s (NIST), The NIST Definition of Cloud Computing and read aloud with me from page 2:

“Essential Characteristics:

“On-demand self-service. A consumer can unilaterally provision computing capabilities, such as server time and network storage, as needed automatically without requiring human interaction with each service provider.”

Can your users do this with your data-center servers? I don’t think so!

“Broad network access. Capabilities are available over the network and accessed through standard mechanisms that promote use by heterogeneous thin or thick client platforms (e.g.,mobile phones, tablets, laptops, and workstations).”

This one sure, if you’ve designed your apps well, this can be done using the good old client-server model we’d used for decades.

“Resource pooling. The provider’s computing resources are pooled to serve multiple consumers using a multi-tenant model, with different physical and virtual resources dynamically assigned and reassigned according to consumer demand. There is a sense of location independence in that the customer generally has no control or knowledge over the exact location of the provided resources but may be able to specify location at a higher level of abstraction (e.g., country, state, or datacenter). Examples of resources include storage, processing, memory, and network bandwidth.”

This one depends on how you’ve designed your data center. Generally speaking, the more able your center is to meet these requirements, the more it’s moving from a simple cluster to a cloud.

“Rapid elasticity. Capabilities can be elastically provisioned and released, in some cases automatically, to scale rapidly outward and inward commensurate with demand. To the consumer, the capabilities available for provisioning often appear to be unlimited and can be appropriated in any quantity at any time.”

This one is cloud-only. You can’t tell me your old-style data center can do this because, quite simply, it can’t.

“Measured service. Cloud systems automatically control and optimize resource use by leveraging a metering capability at some level of abstraction appropriate to the type of service (e.g., storage, processing, bandwidth, and active user accounts). Resource usage can be monitored, controlled, and reported, providing transparency for both the provider and consumer of the utilized service.”

Yes, here’s another one you can “sort of” do with a data center. You can certainly automate system resources to meet demand or to limit a greedy customer to so much bandwidth. Where this moves from data center to cloud is that when you can pool resources together (remember, resource pooling helps define a cloud) into what for the user appears to be a seamless whole service rather than individual resources.

Does this sound like I’m being too picky? I’m not. As Jim Rapoza, senior research analyst and editorial director at the Aberdeen Group, wrote, “Yes, a private cloud is, to a large degree, all about using virtual servers in your infrastructure. But as they say, it’s the details that matter.

And, I might add, actually define what private both is and can be. All these characteristics, properly deployed, will enable you to get more value out of your existing servers than using old, outmoded ways of presenting your data center’s resources to your corporate users.


  1. Fred Summers says:

    Thanks for showing the difference between server banks and a cloud service. I admit I was confused on the difference and this really helps. I like how you add that individually the differences aren’t much but as a whole cloud computing is a much different thing.


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