What is a Private Cloud?

Private cloud is a type of cloud computing that delivers similar advantages to public cloud, including scalability and self-service, but through a proprietary architecture. Unlike public clouds, which deliver services to multiple organizations, a private cloud is dedicated to a single organization.

What is a Private Cloud?

A private cloud is a particular model of cloud computing that involves a distinct and secure cloud based environment in which only the specified client can operate. As with other cloud models, private clouds will provide computing power as a service within a virtualised environment using an underlying pool of physical computing resource. However, under the private cloud model, the cloud (the pool of resource) is only accessible by a single organisation providing that organisation with greater control and privacy.

The technical mechanisms used to provide the different services which can be classed as being private cloud services can vary considerably and so it is hard to define what constitutes a private cloud from a technical aspect. Instead such services are usually categorised by the features that they offer to their client. Traits that characterise private clouds include the ring fencing of a cloud for the sole use of one organisation and higher levels of network security. They can be defined in contrast to a public cloud which has multiple clients accessing virtualised services which all draw their resource from the same pool of servers across public networks. Private cloud services draw their resource from a dsitinct pool of physical computers but these may be hosted internally or externally and may be accessed across private leased lines or secure encrypted connections via public networks.

The additional security offered by the ring fenced cloud model is ideal for any organisation, including enterprise, that needs to store and process private data or carry out sensitive tasks. For example, a private cloud service could be utilised by a financial company that is required by regulation to store sensitive data internally and who will still want to benefit from some of the advantages of cloud computing within their business infrastructure, such as on demand resource allocation.

The private cloud model is closer to the more traditional model of individual local access networks (LANs) used in the past by enterprise but with the added advantages of virtualisation. The features and benefits of private clouds therefore are:
  • Higher security and privacy: public clouds services can implement a certain level of security but private clouds - using techniques such as distinct pools of resources with access restricted to connections made from behind one organisation’s firewall, dedicated leased lines and/or on-site internal hosting - can ensure that operations are kept out of the reach of prying eyes
  • More control: as a private cloud is only accessible by a single organisation, that organisation will have the ability to configure and manage it inline with their needs to achieve a tailored network solution. However, this level of control removes somes the economies of scale generated in public clouds by having centralised management of the hardware
  • Cost and energy efficiency: implementing a private cloud model can improve the allocation of resources within an organisation by ensuring that the availability of resources to individual departments/business functions can directly and flexibly respond to their demand. Therefore, although they are not as cost effective as a public cloud services due to smaller economies of scale and increased management costs, they do make more efficient use of the computing resource than traditional LANs as they minimise the investment into unused capacity. Not only does this provide a cost saving but it can reduce an organisation’s carbon footprint too
  • Improved reliability: even where resources (servers, networks etc.) are hosted internally, the creation of virtualised operating environments means that the network is more resilient to individual failures across the physical infrastructure. Virtual partitions can, for example, pull their resource from the remaining unaffected servers. In addition, where the cloud is hosted with a third party, the organisation can still benefit from the physical security afforded to infrastructure hosted within data centres
  • Cloud bursting: some providers may offer the opportunity to employ cloud bursting, within a private cloud offering, in the event of spikes in demand. This service allows the provider to switch certain non-sensitive functions to a public cloud to free up more space in the private cloud for the sensitive functions that require it. Private clouds can even be integrated with public cloud services to form hybrid clouds where non-sensitive functions are always allocated to the public cloud to maximise the efficiencies on offer.
Private Clouds and Hybrid Clouds
A private cloud is always part of a larger infrastructure. Few if any private clouds fulfill all of a business’s computing needs all by themselves (largely because businesses will probably never be able to fit all their compute resources into a single integrated private cloud.)

Consequently, most private clouds are in fact part of a hybrid cloud deployment. A hybrid cloud is a deployment that includes both a private cloud and public cloud; or some form of in-house and externally hosted cloud – the possible permutations are numerous. (In fact, many companies that believe they are not yet in the cloud are, in reality, already relying on cloud resources.)

For instance, many companies use sales automation software from vendors like SugarCRM, Netsuite and salesforce.com. In classic SaaS fashion, this software no longer resides in the datacenter as it once did; instead these vendors charge a per user license fee and maintain the apps themselves.

So where do the customers store the resulting data? Quite likely in a hybrid cloud: data about potential customers could reside in a lower-cost public cloud; but once these prospects convert to paying customers, their sensitive data is moved safely into an in-house private cloud.

This concept of “more sensitive” vs. “less sensitive” types of data drives much of the move toward the hybrid cloud. A company may outsource its email service to a public cloud service, yet store its most strategic R&D work in a private cloud. Or a firm may have a cloud-based business analytics application that contains only limited data sets, to enable fast number crunching over the Web. Some companies outsource parts of their HR work and allow it to be stored on a pubic cloud, yet for regulatory reasons the company stores sensitive personnel data only on a private cloud.