Private Cloud
A private cloud is an infrastructure that is used only for a single organization, whether handled internally or by a 3rd-party and hosted internally or externally.
The private cloud is a new method of computing in which corporate IT infrastructure is present as a ubiquitous, easily accessible, and reliable utility service.
Business owners and application owners, who want to use a new business service, can use the infrastructure as a standard service, without understanding the complexities of servers, storage, and networks.
Following are the examples of the Private Cloud:
Windows Server 2012 R2
Microsoft System Center 2012 R2
VMware vCloud Suite
IBM SmartCloud Orchestrator
Advantages of a private cloud
Following are the advantages of a private cloud:
The client pays for resources as they are used and allows capacity fluctuations over time.
SLAs and contractual terms and conditions are negotiable between client and the cloud vendor for meeting the particular requirements.
Data and secure information are placed behind the corporate firewall.
Private clouds can be used for particular operating systems and applications, and make use of cases that are unique to the client.
Some cost savings are possible from economies of scale of providers for a large enterprise-wide solution.
Cloud vendor can provide a fully-managed service.
Self-service provisioning of infrastructure capacity is only feasible up to a point.
Public Cloud
A public cloud is based on the standard cloud computing model, in which resources, such as applications and storage are made by a service provider and are available to the general public over the Internet.
The public cloud services can be free or delivered on a pay-perusage model. The public cloud can provide immediate cost savings to an organization.
Depending on the specific requirements of the organization, such as customized configuration requirements and service-level agreements (SLAs) regarding up-time requirements, a company should decide whether to move critical applications to a public cloud vendor.
Following are the examples of the public cloud:
Google App Engine
Microsoft Windows Azure
IBM Smart Cloud
Amazon EC2
NetSuite
Rackspace
SoftLayer
Salesforce.com
Disadvantages of a public cloud
Following are the disadvantages of a public cloud:
The sharing of sensitive data takes place beyond the corporate firewall.
Distance may create challenges with access performance and user application content.
There are limited platform choices available. Support for operating system and application stacks may not meet with the requirements of the client.
A separate provider needs to be found (and paid for) in order to maintain the computing stack.
Advantages of a public cloud
Following are the advantages of a public cloud:
Up-front capital is not investment in infrastructure.
The client pays for resources as they are used and permits capacity fluctuations over time.
There is a simple web interface for self-service provisioning of infrastructure capacity.
There is a possibility of significant cost savings from provider’s economies of scale.
Operating costs for the cloud are absorbed in the usage-based pricing.
Vendors are encouraged to deliver to contract.