Stress Testing Software: A Quick Guide

Stress testing software reveals if your systems can withstand extreme conditions by pushing them to their limits. By pushing your software to its limits, you can identify its weak points and figure out what needs to be fixed, and ensure your software remains stable and reliable when it matters most.

This guide covers what stress testing is, its primary goals, methods of stress testing, and best practices for optimizing your software's performance. Let's get started.

What is stress testing?

Stress testing determines the robustness of software by pushing it beyond its normal operational boundaries until failure. Effectively seeing how software can handle errors and stay available under heavy loads. The results generated by this type of testing are vital across various industries like e-commerce, fintech, healthcare, and telecommunications, & industries where consistent system performance and dependability are critical.

By carrying out stress tests, it becomes possible to detect problems early on. These tests ensure that applications can withstand unexpected peak loads while maintaining stability under strenuous conditions. It evaluates whether the system behavior can endure stress scenarios (this is why stress testing is sometimes called endurance testing) robustly and quickly recover from any disruptions encountered during periods of high demand or atypical use.

Why is stress testing needed?

Stress tests play a significant role in securing system reliability by confirming applications remain stable and functional even when subjected to intensive data loads or high volumes of concurrent users. Some key examples of what stress testing can help: 

1. Accommodate the sudden surges in traffic: Knowing how your app performs under abnormal traffic spikes can make or break many businesses.
2. Display error messages under pressure: Stress testing is important so you can check whether your systems can still display appropriate error messages when under stress conditions.
3. Prepare your systems to work under abnormal conditions: No one can truly see into the future, so ensuring your systems can handle the unexpected when other can't give you a competitive edge and helps win customers.

Types of stress testing methods

There are multiple stress testing techniques, each designed to evaluate different aspects of system performance. These methods range from distributed and application stress testing to transactional stress testing.

Selecting the appropriate method for stress testing depends on the unique needs and features of the software undergoing evaluation.

Distributed stress testing

Distributed stress testing entails the simulation of concurrent server access by numerous clients to assess its performance capabilities. During this process, a designated stress server assigns tests to various clients and monitors their progress, which aids in pinpointing potential vulnerabilities when the server is subjected to conditions of intense load. This form of testing is especially beneficial for determining how effectively a server can manage simultaneous requests from multiple users.

Applications like Loadero are instrumental in performing distributed stress testing across different applications and servers, not limited just to web services. By replicating real-world usage scenarios through distributed stress testing, one can obtain critical insights into a server’s capacity for sustaining its performance levels under substantial loads. Consequently, this contributes significantly towards ensuring that the system remains both robust and dependable.

Application stress testing

Stress testing an application aims to uncover flaws like data locking, connectivity issues, and performance limitations. It scrutinizes the system for potential slowdowns, unforeseen lags, or effectiveness concerns under pressure-packed scenarios to deliver a detailed assessment of how well the application holds up.

By revealing points at which the application may falter, stress testing empowers users to fine-tune their system’s performance and improve overall user contentment. This form of evaluation is especially vital for web and mobile applications due to their fluctuating load conditions and diverse user interactions.

Transactional stress testing

During peak transactional loads, transactional stress testing checks the precision of data exchanges to affirm that systems are capable of managing a considerable number of simultaneous transactions error-free. By doing so, it markedly improves the dependability and correctness of data transactions when under stress.

This type of stress testing can uncover possible security weaknesses in an application. Upholding system performance amid high volumes of transactions is critical for maintaining both data integrity and systemic stability.

How to set up a stress test

The process of stress testing encompasses various stages aimed at verifying the resilience of system performance when subjected to intense conditions. Not only does this testing procedure evaluate the software’s functionality during stress, but it also gauges its ability to rebound from breakdowns, thus providing a thorough method within the realm of software testing.

1. Planning and setup

To execute an effective stress testing process, it is essential to pinpoint the precise systems or hardware that need examination, like which database configurations you use. As well as how your system currently performs and the traffic patterns you are used to handling. Then you have to set explicit goals for the test, like uncovering limitations or vulnerabilities of the system, which is critical to ensure that crafted scenarios are targeted towards achieving those specific objectives.

The undertaking of a stress test can require significant computational resources and time for successful execution. Hence, meticulous planning and preparation constitute key initial steps in laying the groundwork for success.

2. Creating test scenarios

Creating stress tests means needing to create test scenarios that are realistic and specific, which can be achieved by taking into account historical data as well as identifying the risks specific to a particular industry.

In order to accurately replicate real-world conditions, it is essential to understand the complexities introduced by unpredictable virtual users and traffic behaviors. Generating test data for automation testing, along with crafting automation scripts, stands as a fundamental aspect in devising these situations.

3. Executing stress tests

Conducting stress testing entails the utilization of automation scripts to execute and record outcomes for later evaluation. Instruments such as LoadRunner and Apache JMeter are adept at emulating user behaviors, conducting load tests, imposing substantial burdens on servers, and executing performance tests to scrutinize system behavior under stressful conditions.

After adjustments are made in response to stress test results, it is customary practice to repeat the testing process to determine whether these modifications have yielded the anticipated improvements. It is critical during this phase of stress testing to refine both systems and code optimization meticulously to achieve targeted performance standards.

4. Analyzing stress test results

Evaluating the outcomes of a stress test requires a thorough examination to detect performance bottlenecks and issues. The foremost action is to identify any malfunctions or difficulties that appeared throughout the testing phase, and which parts of the system are in need of refinement or optimization. It’s essential to continuously observe the system’s performance during the execution of a stress test in order to recognize any indications of unreliability or unanticipated faults.

Metrics to measure stress test performance

Gathering and analyzing performance metrics is a complicated task due to the diversity of data involved. Essential indicators such as: 

• Response time
• Throughput
• Error rate 
• Pass/fail rates for transactions
• CPU usage and memory consumption
• Latency issues
• Wait periods 
• Number of simultaneous users

These metrics offer valuable information regarding different facets of system performance. Evaluating them helps to pinpoint potential enhancements and guarantees that the system operates at its best when under stress.

Common challenges in stress testing

Stress testing is instrumental in unearthing vulnerabilities and frailties within a system that might otherwise go unnoticed during normal use. Although it excels at pinpointing where problems arise, it often falls short of explaining the reasons behind these issues. To gain a more profound understanding, exploratory stress testing can be utilized for its ability to delve deeper into potential weaknesses.

Simulating an authentic heavy load that accurately reflects real-world user activity presents challenges. Employing sophisticated load testing tools while fostering strong collaboration among development, operations, and QA teams can assist in creating convincing simulations of high traffic environments. This collaborative approach aids in addressing performance issues when faced with numerous concurrent virtual users.

Top tools for effective stress testing

There are multiple testing tools on the market designed for stress testing, each with distinctive features and functionalities. Notable performance testing tools such as Apache JMeter, LoadRunner, and NeoLoad also serve as automated stress testing tools. To their capabilities as load testing tools.

LoadRunner

LoadRunner is extensively employed for automated stress testing, as it can mimic user interactions via a graphical user interface to evaluate how applications perform under substantial loads. This functionality renders it an essential instrument for load tests, performance testing, and creating load generators.

JMeter

JMeter, a Java-based open-source software, is capable of executing multiple testing forms such as load, function, and stress testing. For JMeter operation, JDK5 or higher is required, which allows it to be utilized by a broad user base.

Loadero

Loadero is a web application testing platform specifically designed to run load tests that simulate real-world conditions. Loadero tests how actual users perform when visiting the web application, with each virtual user gathering metrics about test performance, including action duration, CPU usage, and WebRTC-specific metrics like FPS and bitrate. Loadero also offers full-service options where experienced load testing engineers handle test preparation, execution, CI pipeline setup, and script development.

Best practices for stress testing

The process of stress testing includes five crucial stages:

1. Establishing a strategy
2. Developing automated scripts
3. Running the scripts
4. Evaluating outcomes
5. Enhancing the system

By integrating stress tests into the routine development procedures within performance engineering, it allows for consistent monitoring of performance and prompt attention to any arising problems, facilitating early detection of potential performance issues.

To create realistic testing scenarios, one should utilize automated scripts that simulate possible conditions causing stress, like unexpected increases in user load within a test environment. It’s important to continuously revisit and revise your strategies for conducting stress tests and formulating test cases so they remain relevant in response to evolving market trends and technological advancements.

Limitations of stress testing

The efficacy and dependability of stress testing are naturally constrained, which can influence the outcomes it yields. There is a potential for false positives during tests, indicating breakdowns in simulated environments that aren’t indicative of actual operational conditions. Pinpointing the exact reasons behind failures poses difficulties because stress testing tends to reveal where problems arise rather than explaining the underlying causes.

Despite its shortcomings, stress testing continues to be an essential instrument for uncovering vulnerabilities before they cause real-world complications.

Final thoughts

Ensuring software reliability and performance across diverse conditions is critical, and stress testing plays a pivotal role in achieving this. It aids in pinpointing performance bottlenecks while also improving system sturdiness, thus significantly contributing to the improvement of software quality and guaranteeing an uninterrupted user experience.

Whatever industry you work in, stress testing is vital for fast-growing businesses that want to be prepared to grow and scale with confidence. Being able to handle to increased system stress that comes from growing customer bases is what separates the businesses with a growth mindset from those that fall behind.