Public cloud v private cloud

23 Mar 2011

The difference between the private and public cloud and the benefits each one can offer.

The emergence of cloud computing has caused a certain element of concern and confusion among many companies.

With the cloud being heralded as a transformative means of managing IT, much of the terminology has left organisations baffled as to which cloud solution is better for their needs.

One such example is discussions on the public cloud versus the private cloud.

“People often ask me the difference between public and private cloud,” says Adam Grennan, engineering manager at Cisco. “Public cloud is, by definition, public, so it’s available and accessible by anybody. Private cloud is something that you run yourself.

“So, in a private cloud, you’re not getting into a multi-tenancy type situation where you’re not sure what data is being stored or what applications are running alongside yours.

“In both situations, public and private, the management is centralised and the services are distributed. However, in public cloud deployment, you cede control to the cloud provider, whereas in private you retain that control in-house.”

Taking risk into account

Putting sensitive data on a public cloud can certainly be a risky move for many businesses and Andrew Maybin, network services director of Tibus, agrees that companies are right to be cautious.

“The cloud has been known up until now as what we would call the public cloud and that is where the services are often anonymous and on a self-service basis. That platform can be spread across countries or even continents. That’s fine for some applications – it depends on
your end user,” says Maybin.

“The private cloud is a new development in the industry. Same technology, same benefits but developed specifically for one company. This becomes important because if you are a company in the financial services sector – your regulator might mandate that your user’s data must be in a specific jurisdiction.

“That won’t work for the public cloud solution because that data could be anywhere and you can’t guarantee that.

“But in a private cloud solution you could host that data in one area, tick all the technical boxes and meet your mandate, as well.”

The private cloud, as a result, offers a more personalised service, offering better security and control on the data stored. Of course, maintaining a private cloud is much more expensive, requiring more resources to maintain it.

However, Andrew Miller, head of sales and marketing at Unity Technology Solutions, has seen a surge in interest from customers on their private cloud solutions, due to advantages of the opex versus capex model.

“For many of our customers, the availability of capex funding has prohibited customers from starting infrastructure upgrades, new application development projects and other key initiatives.”

Grennan believes that most businesses will mix both the private and the public cloud, depending on the security level of their applications.

EMC’s country manager for Ireland Jason Ward believes that organisations need to put a lot of thought into how they deploy a private or public cloud.

“You’ll have a lot of CIOs being asked: ‘I want to virtualise my desktops and my core mission-critical systems and deploy to any device, whether it’s a laptop, a Mac or an iPod, so how can I do that securely?’” explains Ward.

The private cloud

Many organisations offer private cloud solutions. The Virtual Computing Environment coalition is a collaboration between EMC, Cisco and VMware that provides private cloud solutions in a box.

“This reduces a lot of the associated cost and therefore businesses can reduce capital expenditure and operational expenditure, improve profitability and, in turn, grow their workforce, creating jobs and growing capability,” Ward says.

IBM, too, is making efforts to provide a more secure cloud infrastructure. It’s leading a European consortium of academic and corporate organisations to produce a more advanced private cloud infrastructure called TClouds.

“Data can be gathered everywhere and accessed by anything, but doing so doesn’t come without some risk, including security and data loss,” says Dr Matthias Schunter, technical leader for TClouds and computer scientist at IBM Research, Zurich. “With TClouds, we aim to demonstrate that the rewards in terms of both cost efficiencies and smarter services, such as healthcare and energy, can be achieved by using advanced cloud technology to reduce or, in some cases, eliminate those risks.”

Ultimately, the decision to go with the private cloud or public cloud depends on the needs of the company. While the private cloud may be the most attractive option for businesses with more sensitive information to maintain and mandates to comply with, the public cloud has many benefits, too. It can provide a secure environment for mainstream applications and can be a lot less expensive than going to the private cloud.

Alternatively, companies can store data into both the private and public cloud, depending on the security required.