Scalability testing

Scalability testing, is the testing of a software application to measure its capability to scale up or scale out in terms of any of its non-functional capability. Scalability testing, is the testing of a software application to measure its capability to scale up or scale out in terms of any of its non-functional capability. Performance, scalability and reliability testing are usually grouped together by software quality analysts. The main goals of scalability testing are to determine the user limit for the web application and ensure end user experience, under a high load, is not compromised. One example is if a web page can be accessed in a timely fashion with a limited delay in response. Another goal is to check if the server can cope i.e. Will the server crash if it is under a heavy load? Dependent on the application that is being tested, different parameters are tested. If a webpage is being tested, the highest possible number of simultaneous users would be tested. Also dependent on the application being tested is the attributes that are tested - these can include CPU usage, network usage or user experience. Successful testing will project most of the issues which could be related to the network, database or hardware/software. When creating a new application, it is difficult to accurately predict the number of users in 1, 2 or even 5 years. Although an estimate can be made, it is not a definite number. An issue with an increasing number of users is that it can create new areas of failure. For example, if you have 100,000 new visitors, it’s not just access to the application that could be a problem; you might also experience issues with the database where you need to store all the data of these new customers. This is why when creating a scalability test, it is important to scale up in increments. These steps can be split into small, medium and high loads. We must scale up in increments as each stage tests a different aspect. Small loads ensure the system functions as it should on a basic level. Medium loads test the system can function at its expected level. High loads test the system can cope with a high load. The environment should be constant throughout testing in order to provide accurate and reliable results. If the testing is a success, we should see a proportional change in performance. For example, if we double the users on the system, we should see a drop in performance of 50%.