Uptime – or downtime, depending on how you look at it – plays a huge role in cloud computing, especially as more and more businesses are using it to run business-critical applications. Deciphering how downtime affects public, private and hybrid clouds starts with defining the different types, and identifying their differences.

Public clouds like amazon.com, rackspace hosting services, and google documents, are standard cloud computing models where a service provider offers resources such as storage (Google Documents) or applications (such as Salesforce), that are available to the general public over the internet either for free, or for a fee.

Private clouds are open only to set audience, usually an organization. They can be managed internally or by a third party, and can be hosted internally or externally. A hospital or a college might use a private cloud to manage their applications.

A hybrid cloud is a compilation of at least one public cloud and at least one private cloud. A good example of this is if an organization uses a highly scalable and cost-effective public cloud to store archived data but hosts customer data and mission critical applications on a more secure and stable private cloud.

Downtime affects all three cloud environments because they all run on physical servers subject to faults, disasters, and scalability problems.

Public cloud services face even more risk. When there is a downtime event, your IT staff is unable to address the issue and you must rely on the hosting provider to fix the problem and your server might not be at the top of their list. Most public cloud services guarantee specific SLAs regarding uptime, but often skirt responsibility with carefully worded SLAs.

Private clouds give your IT department access and control of the hardware, and thus, the performance and security of the cloud. Private clouds also give you the ability to run highinput high-output database servers without worrying about the scalability according to someone else’s usage. Control over the specific hardware supporting the private cloud also offers IT professionals the opportunity to use fault tolerant servers or high availability software in their infrastructure, securing uptime for the applications and data.

Hybrid clouds, as you would guess, face both the risks and the benefits of public and private clouds.

To learn more about keeping your cloud up and running, read our whitepaper, “Server Virtualization and Cloud Computing; Four Hidden Impacts on Uptime and Availability.”