Building The Case For Private Clouds: Page 2 of 2

Reliability Significant dependence on mission-critical applications with extreme up-time requirements can be a reason to stick to a private cloud. Public cloud service-level agreements (SLAs) are typically 99.95% to 99.99%, where a properly designed top-tier data center will meet or exceed 99.999%. This means that when utilizing the public cloud, applications with higher up-time requirements must be redesigned to increase the underlying infrastructure availability. If you rely on applications with stringent up-time requirements that can’t easily or cost effectively be re-engineered for the public cloud, then private options may be your best bet.

Lock-in While cloud lock-in is often overstated, it does exist. Depending on your provider or delivery model, lock-in may pose a significant challenge. When designing applications for a platform as a service (PaaS) or building applications around API-driven infrastructure-as-a-service (IaaS) offerings, you will be "locked in" to some extent with that provider. This means it will be more difficult to move services to another vendor once deployed.

Cost Cost is often left out when making a case to utilize a private cloud infrastructure rather than a public one. It’s easy to assume that public cloud will be cheaper than running your own infrastructure. At some tipping point, based on size and IT maturity level, it’s actually cheaper for an organization to run a private cloud. Wikibon defines this tipping point as organizations with revenue or budget of more than $1 billion.

For many organizations, private cloud models are the better option and can provide true business value and possible cost savings.