Enterprise Application Services
Friday, November 16, 2007
Legacy Applications Migration
By [http://ezinearticles.com/?expert=Chris_Young]Chris Young
One of the most common problems encountered by our clients is how to deal with so called "legacy" applications. Often the applications are operating well in dealing with the original business requirements however they may be suffering from an inability to handle rapid growth or to facilitate and support changing business requirements.
Additional issues plaguing these application may be increasing difficulty in finding staff with the necessary technical experience, a lack of up-to-date documentation and ad-hoc addition of new functionality which has not maintained the original architectural design.
Building a new application from scratch is a major undertaking that may squander the investment in analysis and implementation of business rules and collection of enterprise data encapsulated in the existing system. Finding a third-party solution is time consuming and costly and may falter simply because there is no "off-the-shelf" replacement for the existing system.
We have found that a reliable and proven solution to this dilemma is to use a structured approach to migrating legacy applications onto flexible, scalable environments. This methodology is broken into three independent phases, and can be summarised as:
Phase I - Define & Architect:
The first phase of the methodology reviews the current state of the legacy application and maps out a path to migration.
1. Document. The starting point is a comprehensive up-to-date understanding of what the functions the application currently provides, what data is utilised and how is it stored, the business rules and assumptions encapsulated into the application and what process flows are automated.
2. Collect Requirements. Determine the key functional requirements including business needs, performance and scalability targets and any specific dependencies and restrictions.
3. Analyse Gaps. Using the map of the target requirements created above, identify the major enhancements or additions to be applied during the migration process.
4. Architect. A detailed roadmap is produced which outlines the steps that will be taken to move from the existing system to the ideal solution.
Phase II - Migrate:
Once the current state has been documented and a detailed roadmap has been produced, we move to the implementation of the migration strategy.
5. Modularise. Each new modular component is created with a well-defined abstract interface and a clear, logically defined business function. This creates a "services" model in which new or changed services can be deployed rapidly.
6. Model. Information Models are primarily a record of the interaction between applications and the business processes, which support and drive an enterprise.
7. Integrate. By utilising an Enterprise Services Bus (ESB) architecture we provide an enabling platform to support integration of the new service modules into the legacy architecture.
8. Migrate and Extend. The ESB architecture provides a framework for implementing the necessary "service interfaces" that enable data to be accessed and updated as necessary between the two parallel environments.
9. Test. As each new element of the system is modularised and integrated with the Enterprise Services Bus it is then tested through a series of business and system test cycles.
Phase III - Extend:
Once the application is migrated to the new architecture, new services can be added more easily.
10. Migrate and Extend. The ESB architecture provides an extensible framework for implementing new services into the application environment.
11. Test. Each new service is tested to ensure it meets functional, performance and scalability criteria through a series of business and system test cycles.
Rather than waiting years for a "big bang" replacement which may never succeed and which will invariably be outdated even before its arrival, this methodology reduces operational and project risk by delivering incremental improvements in functionality as well as the scalability, flexibility and supportability of the application.
Chris Young is the founder of White Water Consulting ( http://www.whitewater.com.au) and is a senior consultant with a broad knowledge and experience in financial services, change management and information technology. His areas of focus include delivering business-aligned IT strategy and implementing best practices in process improvement, project management and software development process. White Water Consulting provides practical solutions to designing and implementing information technology strategy. By remaining independent of solutions and solution providers White Water Consulting can concentrate on your actual business needs and recommend strategies that are pragmatic and cost effective.
Article Source: http://EzineArticles.com/?expert=Chris_Young http://EzineArticles.com/?Legacy-Applications-Migration&id=794096
Posted By: Illusion Technologies
http://www.illusiontechnologies.com
posted by Illusion Technologies @ 4:22 AM,
1 Comments:
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