How Private Cloud and Public Cloud Computing Compare
In the community of cloud community services, confusion and debate continue over the definition of a private cloud. The phrase private cloud refers to a highly virtualized cloud data center located inside your company’s firewall. The private cloud also may be a private space dedicated to your company within a cloud vendor data center designed to handle your company’s workloads.
The characteristics of a private cloud are as follows:
Allows IT to provision services and compute capability to internal users in a self-service manner
Automates management tasks and lets you bill business units for the services they consume
Provides a well-managed environment
Optimizes the use of computing resources such as servers
Supports specific workloads
Provides self-service based provisioning of hardware and software resources
You might think these descriptors sound quite a bit like a public cloud! A private cloud exhibits the key characteristics of a public cloud, including elasticity, scalability, and self-service provisioning. The major difference is control over the environment. In a private cloud, you (or a trusted partner) control the service management.
It might help to think of the public cloud as the Internet and the private cloud as the intranet.
If private and public clouds are so similar, why would you develop a private cloud instead of ordering capacity on demand from an Infrastructure as a Service (IaaS) provider or using Software as a Service (SaaS)? Here are several good reasons companies are using a private rather than a public cloud:
Your organization has a huge, well-run data center with a lot of spare capacity. It would be more expensive to use a public cloud even if you have to add new software to transform that data center into a cloud.
Your organization offers IT services to a large ecosystem of partners as part of your core business. Therefore, a private cloud could be a revenue source.
Your company’s data is its lifeblood. You feel that to keep control you must keep your information behind your own firewall.
You need to keep your data center running in accordance with rules of governance and compliance.
You have critical performance requirements, meaning you need 99.9999 percent availability. Therefore, a private cloud may be your only option. This higher level of service is more expensive, but is a business requirement.
Some early adopters of private cloud technology have experienced server use rates of up to 90 percent. This is a real breakthrough, particularly in challenging economic times.