A private cloud is defined as a single tenant, dedicated hardware platform which runs virtualisation software to provide an organisation with facilities for running virtual machines and associated services. Given that the infrastructure is not shared, performance and compliance can be guaranteed, and full control of allocated resources is held by the organisation. This offers a significant advantage over public cloud solutions where many virtual machines may be competing for the same resources on the underlying platform.
Many existing private cloud deployments are on-site at an organisation's own premises, requiring significant ongoing maintenance and staff expertise. In addition hardware refreshes of systems can be costly and difficult to implement. A hosted private cloud with a service provider is thus an attractive solution allowing an organisation to take advantage of higher service levels and the latest managed cloud infrastructure for a predictable monthly service fee.
A typical hardware platform includes several high performance host servers that provide the compute resources to run the virtual machines, along with network accessible disk storage in the form of 1 or more SANs. Careful attention needs to be paid to the specification of the infrastructure to ensure service levels are achieved and application performance is satisfactory. In particular, the SANs performs a crucial role in overall system performance.
In a private cloud hosting environment, network switching can either be shared or dedicated. By utilising a shared network environment, costs can be reduced with little significant impact on application performance by utilising the networking infrastructure of the service provider. For organisations with compliance requirements dedicated network switches will be required. Whichever option is selected a detailed examination of bandwidth usage and failover redundancy should be carried out.
Depending on the size of the environment, a typical platform should provide sufficient overhead to allow for failure of at least 1 host server (N+1). In practice most platforms can withstand 2 host servers being unavailable (N+2) which allows for routine server maintenance to be performed on one, whilst still maintaining resilience if a host failure should occur. SANs are always configured with a minimum of 2 controllers.
A good service level agreement is crucial when selecting a service provider. You'll need to ensure that there are fixed response times to any issues regardless of the time of day, with a financial penalty if the service provider fails to deliver. A 3rd party reference is often the best route to satisfying yourself of a service providers suitability.
Moving to private cloud hosting offers many benefits to today's enterprises, freeing IT departments from day to day maintenance and support. With the right service pro