Difference Between Private and Public Clouds

by Paul Rudo on 16/07/12 at 9:15 pm

Cloud computing is revolutionizing the way we think about information systems. Today, it’s hard to think of any area where cloud computing hasn’t touched our lives.

Individuals use cloud-based email and social networking apps to talk to each other.
Small businesses use cloud-based SaaS business apps to run their daily business functions.
Even large organizations rent time on massive cloud server for high-power computation projects.

But when talking about cloud computing, you may occasionally hear a number of computing terms thrown around.

Two of the most common terms you’ll hear when talking about cloud strategy are “Private Cloud” and “Public Cloud”. Have you ever wondered what these 2 terms mean, and how they’re different?

Although cloud computing comes in different flavors, the “classic” concept of a public cloud is a third-party service that allows you to rent virtual servers or server resources (such as memory, hard drive space, processing power, etc…) on an as-needed basis. And the client only pays for what they use.

With public clouds, the client does not need to worry about the maintenance or inner-workings of the underlying hardware or hypervisor. With a public cloud, there are no up-front capital investments and nothing to store in your datacenter.

This is truly computing-as-a-service.

With public clouds, computing becomes a utility in a similar way to how you can purchase electricity from the power company. (Without utility power, everyone would need to buy and install a generator for your back yard)

When public clouds are mentioned in conversation, they’re usually referring to virtualized server hosted on a rented hypervisor in a third-party datacenter infrastructure. But there are other forms of public clouds which can include SaaS and PaaS. (But that’s a discussion for another blog post)

Of course, public clouds aren’t for everyone. There are certain times when you’re willing to spend a more money and take on a larger maintenance burden in exchange for better control.

The “classic” example of a private cloud would be a server infrastructure that is owned by a single company – or group of companies – that is hosted and kept within an internal network. In this example, virtual machines and server resources would be provisioned to internal customers within the organization.

Private clouds are particularly attractive to larger organizations who can afford to spend money on maintaining their own corporate governance, data security and reliability, rather than handing these responsibilities over to a third party.

So how do you decide between the safety of a private cloud or the convenience and cost-savings of a public cloud?

For very large organizations, this paranoia makes sense. But does it really make sense for smaller companies to mistrust the cloud when it comes to security? That depends on what resources they have available to them in-house.

Cloud providers invest heavily on network security, data encryption and data security. Most cloud hosting datacenters have very restricted access policies, 24-hour video monitoring, live security guards, and all of the servers are stored inside of locked cages. Compare this to the average small business server which is kept under someone’s desk… were any thief can come in and steal it.

Unless you’re ready to spend the tens of thousands of dollars to build, support and maintain a secure in-house datacenter, hosting your servers in the cloud will probably be the safer option.