Public cloud vs. private cloud: Why not both?

April 4, 2011 Off By David
Grazed from Network World.  Author: Beth Schultz.

As cloud computing moves from hype to reality, certain broad trends and best practices are emerging when it comes to the public cloud vs. private cloud deployment debate.

Anecdotally and from surveys, it’s becoming clear that most enterprises are first looking to the private cloud as a way to play with cloud tools and concepts in the safety of their own secure sandbox.

Tech Debate: Cloud: Public or private?

For example, a recent Info-Tech survey shows that 76% of IT decision-makers will focus initially or, in the case of 33% of respondents, exclusively on the private cloud.

"The bulk of our clients come in thinking private. They want to understand the cloud, and think it’s best to get their feet wet within their own four walls," says Joe Coyle, CTO at Capgemini in North America.

But experts say a better approach is to evaluate specific applications, factor in security and compliance considerations, and then decide what apps are appropriate for a private cloud, as well as what apps can immediately be shifted to the public cloud.

The public option | Take the fast track to private clouds

Private cloud oftentimes is the knee-jerk reaction, but not necessarily the right decision, Coyle adds. "What companies really need to do is look at each workload to determine which kind of cloud it should be in. By asking the right questions around criteria such as availability, security and cost, the answers will push the workload to the public or private, or maybe community, cloud," he says.

Certainly before moving data to the multitenant public cloud, enterprise IT executives want assurances about the classic cautions around security, availability and accountability of data, agrees John Sloan, lead analyst with Info-Tech Research Group, and IT research and advice firm.

"But I stress, those are cautions and not necessarily red flags. They’re more like yellow flags," he says. That’s because what will assure one company won’t come near to placating another, Sloan adds.

Company size and type of business make a difference. He uses availability as an example. "If you’re at a smaller company and don’t have an N-plus data center, then three-nines availability might be good enough for what you run and, in fact, it might even be better than what you can provide internally. So from that viewpoint, a public cloud service will be perfectly acceptable," Sloan says.

"But if you’re at a larger enterprise with a large N-plus data center and you’re guaranteeing five-nines availability to mission-critical or core applications, then you’d dismiss the public cloud for your most important stuff because it can’t beat what you’ve already got," he adds.

And just as private vs. private doesn’t have to be an either/or proposition, there are still other models, such as hosted private cloud, or hybrid cloud that provide additional options and flexibility for companies moving to the cloud.

If you have major security and privacy issues, and you don’t want to build your own private cloud, a virtual private cloud, your own gated community within the public cloud universe, is an option.