One of ColdFusion's long-standing advantages over other Web development environments is time-to-market. It's not uncommon to hear stories of start-to-finish ColdFusion projects that take less than a month...or even a week. But these ultratight schedules allow little or no time for proper planning and testing prior to launch.

ColdFusion's simplicity and speed of development, which allows for the creation of powerful applications, doesn't reduce the importance of appropriate planning and testing in developing scalable applications. In the end, every Web application undergoes testing for both functionality and scalability. Some are tested prior to release as part of the development process. Others aren't fully tested until after their release, and by unsuspecting customers.

A firm understanding of the nature of rapid development and a brief review of the processes that lay the foundation for scalable application development will allow us to better understand how to achieve scalable applications rapidly.

Rapid Development for the Web
ColdFusion isn't the first product to offer rapid development other non-Web tools have similar accelerated development cycles. What is special about rapid development for the Web? The big difference lies in the deployment environment.

First, in the client/server world applications are generally released to a predictable, relatively small, restricted number of users in a controlled environment.

Web applications on the other hand are often released to an un-known, virtually unlimited number of potentially simultaneous users in the frequently unpredictable environment of the Web.

Second, while rolling out a client/server application often requires a significant effort, the effort required to deploy a Web application can be minimal. By simply deploying a code set to a single Web server, you can immediately reach thousands of users.

The possibility that you could so easily deploy an application to hundreds of thousands of simultaneous users adds significant risk to an application that wasn't developed with proper development methodology - and to the company behind it. With sound development practices, however, these risks can be minimized while still achieving rapid application development.

Scalable Application Development
Regardless of the development tools you use, the same basic principles of sound development hold. Appropriate resources need to be allocated for architectural planning, site reporting, database tuning, code analysis and tuning, representative staging, load and regression testing, server tuning, spike readiness, recovery planning and monitoring. While ColdFusion can substantially compress the time needed for some of these stages, it doesn't reduce the need for a proper development process.

A number of key considerations come into play when developing and deploying scalable Web applications. The information below is excerpted from a more detailed Allaire Knowledge Base article, #12970, available at http://www2.allaire.com/Handlers/index.cfm?ID=12970&Method=Full:

1. Architectural Planning
Plan the deployment, staging and development environments before launching your Web application. At the same time, growth requirements, security, proper testing and potential points of failure should be kept in mind. To better structure your code, understand your application's scalability requirements and existing constraints before starting development.

2. Site Reporting
Design your site with reporting in mind. Site reporting can range from log analysis to business and marketing trends to usage analysis. At its most basic level, it can provide useful diagnostic information about the relative traffic to different portions of your application or Web site. This information can be invaluable for troubleshooting and site planning. More sophisticated reporting can sometimes offer detailed information about site traffic, including the correlation of such information to back-end databases for more descriptive reporting. Some development architectures facilitate reporting while others hinder it.

3. Database Tuning
Run the database server(s) well below 50% of capacity to allow for load spikes. The vast majority of performance bottlenecks in database-driven applications stem from poorly tuned databases and queries. Every database-driven application can benefit from the active participation of a skilled database administrator (DBA) for both query and database tuning.

4. Code Analysis and Tuning
Consider a variety of alternative coding constructs to achieve optimum functionality and performance. Bear in mind that some are more efficient than others for a given task. Best-practices documents and the ColdFusion Server debugging features, including page-processing statistics, can facilitate your code quality analysis.

5. Representative Staging
Include allowances for application testing in a representative staging environment. You can use this environment to detect and correct deployment configuration issues before reaching final deployment.

6. Load and Regression Testing
Test your applications thoroughly for both functionality and performance under load. Many Web applications and sites in use have been only marginally tested under load prior to deployment, if at all. These applications often work fine under minimal or moderate load, but become unstable or unbearably lethargic under heavy load.

7. Server Tuning
Tune your servers thoroughly. Proper and thorough server tuning can often achieve significant performance improvements. Each Web application has its own distinct demands, stressing specific server resources and often requiring a distinct server configuration for optimal performance.

8. Spike Readiness
Plan for load spikes and develop contingency plans for rapid emergency system expansion. Load spikes can come when you least expect them. Your systems should be able to handle at least twice the regular peak load without additional resources. The extra bandwidth not only protects you against unexpected load spikes, it also can ensure application availability during unexpected partial outages or system maintenance.

9. Recovery Planning
Make a contingency plan for every possible failure point in your application deployment environment. Determine your acceptable downtime threshold, and plan your contingency plans accordingly.

10. Monitoring
Plan for monitoring. A scalable, stable Web project often involves various forms of monitoring, be they implicit or explicit. Any portion of your deployment environment that can fail is a candidate for some form of monitoring, be it periodic manual verification or some form of automated detection.

Conclusion
Tag-based technologies like ColdFusion provide extremely productive, scalable, rapid-development tools that can substantially reduce your time and costs of developing, deploying and maintaining Web applications. Remember, however, that they're not alternatives to proper development methodologies. They are catalysts to accelerate various stages of those methodologies.

As Web technology evolves, we'll continue to evolve our products to make those technologies imminently usable and accessible to Web developers. Web technologies will come and go, but sound development practices are here to stay.