Java Testing and Design - 2.2 Defining Criteria for Good Web Performance

The author asserts that three criteria must be checked if you are to determine if your web application is healthy:

• are the features working?
• is the performance acceptable?
• how often does it fail?

Create a short list of the most important features of your application and create automated tests for them.  Consult real users and find out how long they will wait for a feature before abandoning it and moving on to something else.  Consult your server logs to find out exactly how often the system fails. Once you know that, you decide if the failure rate is too high for your situation.