Public vs. Private Cloud Computing
Whether a public cloud or private cloud, everyone agrees that cloud computing key benefits include scalability, instant provisioning, virtualized resources and ability to expand the server base quickly.
The majority of public cloud deployments are generally used for quality assurance testing, or where user demand peaks and falls at certain times of the day, month or year. Generally, security and compliance requirements is not an issue. Private cloud computing, on the other hand, by definition is a single-tenant environment where the hardware, storage and network are bought by and dedicated to a single client or company.
The public cloud is defined as a multi-tenant environment, where you buy a “server slice” in a cloud computing environment that is shared with a number of other clients or tenants.
Public Cloud Computing
Public clouds such as Amazon EC2 and Microsoft Azure have a number of trade-offs:
- Utility Model – Public clouds typically deliver a pay-as-you-go model, where you pay by the hour for the compute resources you use. This is an economical way to go if you’re spinning up and tearing down development servers on a regular basis.
- No Contracts – Along with the utility model, you’re only paying by the hour – if you want to shut down your server after only 2 hours of use, there is no contract requiring your ongoing use of the server.
- Shared Hardware – Because the public cloud is by definition a multi-tenant environment, your server shares the same hardware, storage and network devices as the other tenants in the cloud.
- Self Managed – With the pay-as-you-go utility model, self managed systems are required for this business model to make sense. There is an advantage here for the technical buyers that like to setup and manage the details of their servers, but a disadvantage for those that want a fully managed solution.
Most public cloud deployments are generally used for web servers or development systems where security and compliance requirements of larger organizations and their customers is less of an issue.
Private Cloud Computing
Private cloud hosting by definition is a single-tenant environment where the hardware, storage and network are dedicated to a single client or company. A more common private cloud computing solution is virtual private cloud hosting, a multi-tenant environment where companies achieve isolation while keeping costs down by buying server slices with other tenants.
Private cloud computing also has a number of trade-offs:
- Security – Because private clouds are dedicated to a single organization, the hardware, data storage and network can be designed to assure high levels of security that cannot be accessed by other clients in the same data center.
- Compliance – Sarbanes Oxley, PCI and HIPAA compliance can be delivered through a virtual private cloud or fully private cloud deployment, because the necessary hardware, data storage and network configurations are dedicated to a single client.
- Customizable – Hardware performance, network performance and storage performance can be specified and customized in the private cloud.
- Hybrid Deployments – If a dedicated server is required to run a high speed database application, that hardware can be integrated into a private cloud, in effect, hybridizing the solution between virtual servers and dedicated servers. This can’t be achieved solely in a public cloud.
As opposed to public clouds, fully private clouds are not delivered through a utility model or pay-as-you-go basis because the hardware is dedicated. However, virtual private clouds offer the same pay-as-you-go model as public clouds, with the added bonus of specifically provisioned hardware, network and storage configurations. Private clouds are generally preferred by mid and large size enterprises because they meet the security and compliance requirements of these larger organizations and their customers.