Implementing SaaS Solutions with IBM middleware, part 1th

A WEB delivery solution that conforms to the software as a service (Software as a Service,saas) delivery model where customers subscribe and access software from the service provider site, Instead of acquiring licenses and installing software in your own environment, you can offer compelling business value to businesses of any size. Solution developers who develop new solutions or transform existing solutions, as well as service providers that deploy these solutions, face a number of technical challenges. Multiple leases (multitenant) is an example of a single software instance running in a service provider environment that serves multiple organizations. This series of articles will describe the different patterns that typically address these issues using service-oriented architecture (SOA) technologies. It also describes how IBM® software products can help you build and deploy a multi-tenant solution for scalable, configurable, and cost-efficient Web delivery.

What are multiple leases, and what are their advantages and disadvantages.

The ability to deliver software to multiple client organizations (or tenants) from a single shared instance of the software is an important requirement for a WEB delivery solution. For example, suppose you have a simple banking application that is provided by a banking service provider as a service. Multi-Tenant in this context refers to the ability to provide banking services to multiple banks from a single shared instance of a banking application. Figure 1 illustrates the multi-tenant banking services offered to two banks (North Carolina State First Bank and Canada Second Bank) from shared application servers, databases, operating systems, and physical servers. Figure 1. Example Web delivery multiple-lease services built for banking with shared middleware and hardware

The main advantage of multiple leases is that they are cost effective. Sharing software, hardware, application development, and maintenance costs among tenants can reduce the cost per tenant. Also, sharing a single instance of an application among tenants can provide additional benefits, such as when an application is upgraded, all tenants can upgrade at the same time.

However, multiple leases can also pose potential problems, such as:

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