With software development being required to scale up faster with optimized quality, testing is now taking center stage. Capacity Testing exercises the system to check if the application and infrastructure can actually take on the amount of traffic that they were designed to handle without compromising user experience. This also helps with planning and design of the infrastructure to optimize quality.
What is Capacity Testing?
Capacity Testing ensures that the application and environment can smoothly handle the maximum number of users or transactions according to the performance requirements defined in your Service-Level Agreement (SLA). Capacity Testing is aimed at testing the maximum capacity of your system in terms of traffic, while still being able to deliver optimal user experience.
Common examples for performance SLAs include homepage load times, webpage response times, transaction durations (e.g., – account login, search, and payment times). The overall objective is to identify the ‘safety zone’ of the system and keep it there as much as possible. Capacity Testing helps determine the extent to which it can be stretched without hurting end user experience.
This is crucial business data. It is well known that 40% of users will abandon a site if it takes more than 3 seconds to load. Just a one second delay can cause small to medium sized eCommerce websites to bleed over $250,000 annually.
Whether it is system or application software, the modern organization needs to know its performance data, as a sales tool and also to create quality benchmarks to improve long-term planning for maximum business profit.
Knowing the application limitations can motivate the organization to improve development processes and deploy a more powerful infrastructure if needed. There should be no performance drop during peak times. This matrix calculation is only possible with Capacity Testing, which helps determine the number of users that can use the system with the optimal user-experience (performance) under different user cases and scenarios.
Capacity Testing is not to be confused with Load Testing, which is more about subjecting the application and environment to varying loads to learn about their behaviour. For example, Load Testing is used to learn how a system behaves with large and varying numbers of users by checking the response time received for pages or transactions under different scenarios. This type of testing is typically performed during the QA stage of software development.
Capacity Testing is also different from Stress Testing, which involves testing beyond operational capacity and subjecting the system to extreme conditions to deliberately try to break the system while observing its behaviour. It is carried out prior to deployment to locate misconfigurations and server vulnerabilities.
Benefits of Capacity Testing
Many organizations report spikes or surges in annual business volumes due to regular, seasonal, and sudden demand for their products. The COVID-19 plagued 2020 is a great example of a surge in online activity. The system design should be able to withstand this sudden surge without sacrificing user experience. This can immediately improve your Capacity Planning.
- Improved Capacity Planning – Traffic estimates are helpful as inputs to the planning process, but only Capacity Testing can help you achieve optimal performance results as per your performance SLAs. Capacity planning helps understand what is the maximum number of transactions or users per system/infrastructure configuration (or configurations).
- Optimizing Resource and Time Usage – Capacity utilization data will eventually help you prepare better for peak times or when your organization is scaling up fast. You will get an exact idea of the maximum load you can handle successfully with your available hardware, memory, and network resources, following which you can spend money on additional resources as per your SLA requirements.
- Enhanced Planning – Capacity Testing provides decision makers with actionable insights to make better use of their infrastructure and also create more realistic performance SLAs that are in-sync with upcoming events and changes. You will also be able to create and manage benchmarks that can be shared with all relevant stakeholders, something that reduces cross-department friction and boosts productivity.
- Better Peak Time Performance – With proper Capacity Testing, organizations can be better prepared for sudden surges in business volume. This is extremely helpful in situations where demand spikes unexpectedly due to unpredictable circumstances. Take a look at medical insurance companies after a natural disaster or military tech companies getting more orders at the time of war or hostilities.
- Compliance – Not all application code was created alike. Capacity Testing can also help reveal and uncover hidden vulnerabilities and loopholes in your ecosystem. It can detect exploitable flaws that creep up along with the aforementioned application and infrastructure performance issues.
Top 5 Capacity Testing Best Practices
As explained earlier, a fraction of a second of delay or poor performance can lead to extensive losses that add up to millions of dollars in today’s uber-competitive market, where customers are demanding optimal quality (e.g., – page load times, duration of transactions) with fast time-to-market. Numerous factors could affect the software’s performance and it’s response time.
An organization planning to deploy an application needs to have a realistic grasp of the load limitations of a given infrastructure under different use cases, business processes, and conditions. It needs to make sure to test against the right SLAs and performance metrics, against the right use cases and business processes and against varying, diverse and realistic user conditions simulating the experience of real users in the production environment.
This helps detect and mitigate the factors that may impact the performance and user experience. Capacity Testing helps identify the right infrastructure for different user scenarios and business needs, ensuring that the customers get an optimal and consistent user experience regardless of the circumstances (e.g., – holiday season, product launch, the beginning of the school year).
Here are some Capacity Testing best practices you should consider.
Best Practice 1: Define Processes and Stick to the 80/20 Rule
Before even getting started with Capacity Testing, you should be creating Pareto charts, not before identifying the stakeholders that are most relevant to the testing and determining the processes that will actually be tested. The most common people involved in Capacity Testing processes are Database Administrators (DBAs), developers, SMEs, product owners, and business executives.
Furthermore, it’s highly recommended to stick to the 80/20 Rule, which can be applied to all aspects of Capacity Testing – performance, load, volume, and more. By applying the 80/20 rule to your Capacity Testing, you can focus on the more problematic and volatile processes that are likely to affect the organization’s profits and create the biggest bottlenecks.
Best Practice 2: Set Proper Criteria and SLAs
Sometimes the automated test tool used before the deployment to the production environment may not understand the business processes associated with the application or the most generated traffic business processes. To avoid these loopholes, the automation engineer should consult with the Product Owner, SMEs, and business analysts for the real-life use case.
You need to make sure that the SLAs you are testing against are realistic, accurate, and relevant to the most important use-cases.
Best Practice 3: Detailed Performed Test Specification
Before conducting any test or capacity test, it is recommended to document the detailed test specification, which can include various parameters like the hardware specification, the version of the Software and Client type, if any (thick, thin), the number of processes running in the background, volume test, type of network, data volumes, and other relevant database details.
You should also factor in the environment type into your Capacity Testing process. Knowing and defining whether it is QA, Sandbox or Pre-Production environment will let you duplicate the production environment in the best possible manner. The more detailed information you can create while testing, the closest you will get to remediating potential issues.
Best Practice 4: Automate for Consistency
It’s recommended to repeat the Capacity Testing and run it continuously with different data sets to fine-tune the app and infrastructure. Some unidentified issues get reported with a different set of data or are plagued with memory-related issues, which can happen after a few test runs. By reducing manual intervention, some intermittent problems also will get identified after a few test runs. Automate the process for better results.
With more and more organizations scaling up exponentially, there are limited available resources. Automated Capacity Testing, integrated to your CI/CD pipeline, is the best way out.
Some capacity test automation tools have the limitation of providing only black-box results, making it very difficult to isolate the issue and pinpoint the root cause of a particular problem. This is a crucial part of capacity planning. If possible, go for the advanced tool, which will help monitor the white box result as well. When your business is time-sensitive, it can’t wait for a different report from the black-box test.
Best Practice 5: Reporting and Comparing Results
Cross-department friction is to be found in all organizations today, at one level or another. This is especially common when there are bottlenecks or during unexpected downtimes. These unpleasant instances can be reduced or eliminated with proper Capacity Testing. By creating comprehensive reports that can be shared with the key stakeholders, you can improve transparency and boost collaboration between departments.
Capacity Testing reporting should always include response time numbers, transaction metrics, error percentage, throughput, and server utilization. Once these performance metrics are available and accessible to all relevant stakeholders, it also becomes easier to analyze performance history and plan design improvements to keep on improving.
Besides the aforementioned Capacity Testing best practices, you should be conducting capacity tests for different infrastructure configurations and sizes (CPUs, memory, etc.). With most websites now serving audiences from different parts of the world, it’s also important to run Capacity Tests with different network conditions and also for different geographical locations.
Capacity Testing – For a Better Bottom Line
To sum it up, your performance SLAs need to be set, enforced, and tested constantly to achieve the organization’s business and financial goals.
With time to market and code quality becoming increasingly important, you need to improve your Capacity Planning with Capacity Testing to determine the right infrastructure for each given scenario. This is the only way to avoid surprises, keep customers happy, create an optimal user-experience, and optimize quality to increase revenue in a sustainable manner.
