Private Cloud vs Public Cloud
Cloud computing is a style of computing in which resources are made available over the internet. Most often these resources are extensible and highly visualized resources and they are provided as a service. Cloud computing is broken down in to three categories, namely SaaS (Software as a Service), PaaS (Platform as a Service) and IaaS (Infrastructure as a Service). Depending on the location of deployment, clouds are divided in to two types as private and public clouds. As the names suggest, public clouds allow its content to be accessed by all through internet, while private clouds only allow corporate users or those that have been approved. However, the internal computing model and infrastructure, which allows for hosting services is very similar in both private and public clouds.
Public Cloud
Public cloud is offered as a service over the internet. Usually, the users of public clouds will pay on a month-to-month basis for the usage of service per bandwidth. Users do not need to buy any storage hardware as it provides on demand scalability. It is the responsibility of the company that provides the service to mange the infrastructure and the set of resources. Since the users of public clouds do not need to buy software or hardware beforehand, the initial cost is minimal. Volume of data in a public cloud could vary from just a back-up of a single laptop to an application in the range of Gigabytes. In a public cloud, the cost increases with the duration of the data storage, therefore they are much more suitable for dynamic data.
Private Cloud
Private cloud is deployed within a firewall and its management is handled by the corporate enterprise, which provides the service. Usually, the customer provides the hardware necessary to operate the private cloud. Storage is not typically shared by anyone other than the enterprise and it is controlled by the company. Similarly, the users fully manage the architecture of the cloud as well. Because of this, the enterprise can extend the cloud by adding more servers to improve the performance and capacity. Private cloud is highly scalable due to its self-managed nature. Private clouds are usually started with few Terabytes and later expanded as required by the enterprise by adding new nodes. In a private cloud, duration of storage usually does not affect the cost. Therefore they are ideal for archiving data for longer periods.
What is the difference between Private Cloud and Public Cloud?
Although both public and private clouds use a similar internal computing model to host services, they have several key differences. Main difference is that a private cloud is always deployed within a firewall, while a public cloud is available over the internet. Because of this, a public cloud is more suitable if users are spread all over the world because private clouds are usually accessible only over the LAN. In private clouds, the enterprise has greater control over the level of isolation, security and privacy of data than in public clouds. Public clouds can be less costly than private ones, as the user is not required to buy resources beforehand.