"Computer resources of providers that are pooled to serve many consumers use a multi-user model, with different resources are distributed according to static and dynamic consumer demand.
There is a certain independence of users when using the service, but the customers don’t control the location of services or where the materials are stored and processed. "
A traditional IT model often focuses on providing IT services for a business. Because they have to allocate greater resources to meet the demand, while the cloud computing service providers can maintain the maximum level of service with minimal resources. For consumers, this means customers can use a maximum service at low cost. That's a major reason why the cloud, unlike traditional models, is expected to be a success.
Having consumers from different industries and countries can help significantly. The domestic industries have changed the usage habits because of climate and cultural differences.
Computer resources can be shared in the infrastructure, platform, or application level. Most people use cloud computing are sharing infrastructure and platforms. Sharing platforms and applications does not mean that users can use all of the programs of the operating system and application programs. From an application perspective, the applications can allow sharing, requiring expansion and reconstructing the software. This may not be worth doing, as the important benefits of using resources efficiently can only be obtained by combining infrastructure resources and platforms.
Efficient use of natural resources is one side of the coin with aggregate resources; Multi-tenancy is the other.
Multi-tenancy means that a single instance of a computer's resources serving multiple client organizations (tenants), providing a separate environment for each.
Multi-tenant housing often involves fault isolation, resource isolation, and security isolation. These capabilities allow tenants to have safe, available environment regardless of the other tenants’ behavior.
How to have many people to rent and use service model. In the case of IaaS, many people hire the same infrastructure which enabled by virtualizing all infrastructure resources. For PaaS, many people hire the same platform which is enabled by the software platform providing a separate environment for the use of its organizations. In this sense, a multi-user operating system can be considered as multiple people using in an environment separate from the other environments. For SaaS, multi-tenant of a software application depends on the applications that are designed to partition configuration and data for the client organization. Most of today's applications are designed for a single tenant, and cannot be changed to multi-tenant operations without significant restructuring.
From the perspective of the viewers, it is difficult to distinguish a multi-tenant applications and a single application running on which a tenant is running with a multi-tenant platform, or to distinguish a multi-tenant platform from a single platform a tenant is running on the tenant based on infrastructures of homeowners.
Each consumer should consider whether there is any impact of sharing with other consumers. It may be difficult to establish the extent to which sharing takes place, without knowing the other consumers. Providers offer consumers different amount of information and their system, which may include very specific product configuration and improvements made specifically to fit the users’ standards. They can provide guarantees of service levels and security, or provide very little by guarantee. You must assess the risks and make your own judgment.