Public cloud vs. Private cloud

Public cloud and Private cloud – over the last few years we hear these two word combinations more and more often when it comes to building company’s infrastructure or when deciding whether to stay with the old and tested solution in the form of its own infrastructure or whether the time has come to transfer not just data but even the applications into a cloud solution.
What is the difference between a Public and Private cloud?

Public cloud is a solution provided by a big and well-known provider such as Amazon, Google, Microsoft, Rackspace, etc. With this service one “rents” a disc space and a processor performance. Most of these solutions are very simple and based on monthly pay-as-you-go models. A client has the ability to specify the space and performance requirements, but his/her server will always be located based on the provider’s needs. Public clouds do not allow clients to choose their hardware, its performance requirements or a more detailed specification. Hardware is therefore shared among a few clients simultaneously. In real life that means that a few virtual server clients run simultaneously on one hardware server. Public cloud is a sufficient solution for a majority of clients with low demands.
Main features of Public cloud are as follows:
– A utility model – pay-as-you-go model based on a per hour fee for computer resources
– No need for contract
– Shared hardware
– No control of hardware performance
– Self-managed solution

On the other hand, Private cloud is most of the time supported by specialized companies or the above mentioned big providers, but on a completely different level. With this solution, a client specifies his/her hardware requirements, its performance, security, etc. And because Private cloud solution is always built on the principle of creating a hardware infrastructure for a specific client, compared to Public cloud it allows to set a substantially higher level of security. Most of the time, Private cloud is not built on a pay-as-you-go model and it requires a term contract with an advance payment. That is another reason why Private cloud is used mainly by medium to big size companies that are able to utilize the advantages of Private cloud for themselves, as well as for their clients. Private Cloud is also appropriate for HIPAA, PCI and other standards, because the hardware is dedicated to one specific client and it is not shared as is the case with Public Cloud.
Main features of Private Cloud are as follows:
– Security
– HIPAA, PCI etc. compliance
– Customization
– Hybrid deployments