What is Soak Testing? How to Design a Soak Test

Testlio

November 15th, 2024

Long periods of operation often reveal problems like memory leaks, resource exhaustion, and degradation of performance. Soak testing, a critical component of performance testing, addresses these challenges by evaluating how a system performs under a significant load over an extended period. 

This method helps detect memory leaks, resource leaks, and performance degradation that could compromise system stability.

In this article, we will explore soak testing, its key components, including design, and examples from real-world scenarios. We will also explore common challenges faced during soak testing and provide practical solutions to overcome them.

What is Soak Testing?

Soak testing evaluates how software performs when used continuously over a period of time. The main goal is to identify long-term issues that may not surface in shorter tests.

A soak test should ideally run for as long as possible, but the duration will depend on the system being tested. 

Now that you understand what soak testing is, here are some scenarios where soak tests might be applied:

• Bank Closure: When a bank announces its closure, the system must handle a large volume of transactions during the final days of operation. This is an unusual and unexpected event, but the system must manage it effectively.
• No On-Call Workers: A system must operate without on-call support, usually over weekends when staff are not available. A soak test in this scenario would test whether the system could run continuously for a period longer than a weekend.

When Should You Conduct Soak Testing?

A soak test verifies that software applications don’t degrade in performance or fail during prolonged use. 

Here are the key scenarios when soak testing should be conducted:

Before Release

Soak testing is typically performed just before deploying a new version of an application. This helps assess its stability and performance under continuous usage, ensuring it can handle real-world conditions effectively.

After Significant Changes

Soak testing is crucial whenever major changes are made to the IT infrastructure – such as upgrades to the operating system, database migrations, or hardware replacements. It verifies that the application will continue to function as expected in the case of continuous loads.

Anticipated Peak Usage

If an application is expected to experience heavy usage during specific periods (e.g., seasonal peaks, promotional campaigns), soak testing beforehand can identify potential problems.

During Performance Testing Phase

Soak testing should be integrated into the performance testing phase of software development, following functional testing. This ensures that any long-term issues are identified before the software goes live.

Off-Peak Hours

The ideal time for conducting soak tests is during off-peak hours, such as weekends or overnight. This allows for uninterrupted testing over extended periods, which is critical for observing how the application performs under sustained usage.

What are Some Commonly Detected Issues?

The goal of soak testing is to identify specific performance-related issues that may not be apparent after a short testing cycle. Here are the key issues it can uncover:

Memory Leaks

Memory leaks occur when an application fails to release memory that is no longer needed, leading to increased memory consumption over time. Due to this overflow, the application may slow down or crash as available memory runs out. 

Soak testing helps detect these leaks by monitoring memory usage continuously over an extended period.

Database Resource Utilization

Database Resource Utilization refers to how well the application manages database connections and resources. Problems such as failing to close database connections or cursors can lead to resource exhaustion, causing the application to stall or crash under load. 

Soak testing monitors these behaviors to provide efficient resource management throughout prolonged usage.

Performance Degradation

Performance degradation increases response times and decreases throughput when the system processes requests over time. This can occur due to inefficient internal data structures or resource management problems that only become apparent under sustained stress. 

Through soak testing, teams can identify and fix any degradation in performance before the application goes live by continuously assessing performance metrics.

Key Components of Soak Testing

Soak testing is an important performance testing method that evaluates how a system performs under sustained load for a prolonged period of time. 

The following are the key components in conducting soak testing:

Test Environment 

You need to replicate the production environment as closely as possible, including hardware, software, network configurations, and everything else. The goal is to ensure that the test results are as accurate and applicable as possible.

Test Scenarios and Workload Profiles

Test scenarios are designed to represent real-world scenarios. This involves creating scenarios that reflect typical user interactions and system loads over an extended period. For example, if the application is an e-commerce platform, the test scenarios might include continuous browsing, adding items to the cart, and completing purchases.

Additionally, cross-platform scenarios should be incorporated to simulate the user journey across different interfaces, such as web + mobile web, web + mobile web + app, or web + app, ensuring seamless functionality and performance across all touchpoints.

Monitoring Tools

Soak testing requires monitoring tools to track CPU usage, memory consumption, disk I/O, and network activity. They help identify performance bottlenecks and resource leaks that might not be apparent in shorter tests.

Duration

Soak tests are typically run for extended periods, ranging from several hours to several weeks. Test duration depends on the application’s expected usage patterns and the specific test objectives. Extended durations help uncover issues like memory leaks that can degrade the system in the long run.

Resource Utilization

Continuous monitoring of resource utilization is critical. This includes tracking how the application uses CPU, memory, disk, and network resources over time. You can spot inefficiencies and potential areas of improvement by looking at resource usage trends.

System Recovery

Soak testing involves assessing the system’s ability to recover from failures or crashes. Tests include how well the system handles shutdowns, restarts, and other disruptions. Therefore, strong recovery mechanisms should be in place to maintain system stability.

Real-World Data

A realistic test data set is important for accurate results. This means using data that closely resembles what the application will encounter in production, including the volume and variety of data. Realistic data helps ensure that the test scenarios are valid and the results are accurate.

Analysis and Reporting

After the soak test, a thorough analysis of the collected data is necessary. This involves identifying any performance issues, resource leaks, or other problems that were uncovered during the test. Stakeholders can gain insight into the system’s performance and stability by reviewing detailed reports.

How to Design a Soak Test?

Soak tests require several steps to make sure that the software application can handle prolonged usage without crashing. Here’s an overview on how to design an effective soak test:

1. Define Objectives

The first step is to clearly outline the goals of the soak test. The objectives typically include identifying memory leaks, resource leaks, performance degradation, and ensuring system stability over extended periods.

2. Identify Key Metrics

Next, you need to determine which performance metrics are crucial for your application. These typically include CPU usage, memory consumption, disk I/O, network throughput, and response times.

3. Create Realistic Test Scenarios

After key metrics, you should develop test scenarios that mimic real-world usage patterns. This involves understanding how users interact with the application and creating scripts that simulate these interactions over an extended period.

4. Set Up the Test Environment

Then, ensure that the test environment closely mirrors the production environment. This includes hardware, software, network configurations, and any other relevant infrastructure components.

5. Implement Monitoring Tools

Following this, you should use monitoring tools to track system performance and resource utilization continuously. Tools like Grafana, Prometheus, or New Relic can help visualize and analyze the data collected during the test.

6. Determine Test Duration

Next, you need to decide on the duration of the soak test. This should be long enough to uncover issues that only appear after prolonged usage. Common durations range from several hours to several weeks, depending on the application’s expected usage.

7. Execute the Test

Then, run the soak test according to the defined scenarios and duration. Ensure continuous monitoring and logging of performance metrics throughout the test period.

8. Analyze Results

After the test, you need to analyze the collected data to identify any performance issues, resource leaks, or other anomalies. Look for trends that indicate degradation over time.

9. Report Findings

Next, you should document the findings in a detailed report. Include graphs and charts to illustrate performance trends and highlight any issues discovered during the test.

10. Implement Fixes and Optimize

Following this, you need to work with the development team to address any identified issues. Optimize the application and infrastructure to improve performance and stability.

11. Re-Test

Finally, you should re-run the soak test after implementing fixes to ensure that the issues have been resolved and that no new issues have been introduced.

Analyzing Soak Test Results

Analyzing soak test results is crucial for identifying long-term performance issues and ensuring system stability. 

Here is a quick overview guide on how to properly analyze soak test results:

• Collect Data Continuously: Gather real-time data on CPU usage, memory consumption, disk I/O, network throughput, and response times using monitoring tools.
• Identify Trends and Patterns: Look for gradual changes in performance metrics to spot potential issues like memory leaks or resource exhaustion.
• Compare with Baseline: Check soak test results against baseline metrics from shorter tests to identify significant deviations.
• Correlate with System Events: Link performance metrics with system events (e.g., garbage collection, database queries) to find root causes of issues.
• Check for Resource Leaks: Detect memory and other resource leaks by analyzing usage patterns for continuous increases without releases.
• Review Logs and Alerts: Examine logs and alerts for errors, warnings, and anomalies that occurred during the test.
• Generate Detailed Reports: Summarize findings with graphs and charts, and provide recommendations for improvements.

Benefits of Soak Testing

Soak testing, also known as endurance testing, offers several significant benefits that help ensure the stability and performance of software applications over extended periods. 

Here are some key benefits:

Identifies Performance Issues Over Time

Soak testing helps uncover performance issues that may not be evident during shorter test cycles. By running the application under continuous load for an extended period, it reveals problems like memory leaks, resource leaks, and performance degradation.

Detects Memory Leaks

One of the primary benefits of soak testing is its ability to identify memory leaks. Memory leaks occur when an application fails to release memory that is no longer needed, leading to increased memory usage over time. Soak testing helps detect these leaks by monitoring memory consumption throughout the test.

Validates Resource Utilization

Soak testing helps identify inefficiencies in how the application uses CPU, memory, disk, and network resources. This allows developers to optimize resource management and prevent potential bottlenecks.

Improves User Experience

Applications that can handle prolonged use without performance issues contribute to a better user experience. Soak testing ensures that the software remains responsive and efficient during extended sessions, which helps build user trust and satisfaction.

Verifies Long-Term Reliability

Soak testing demonstrates that an application can reliably handle the expected load over time. This is particularly important for applications that are expected to run continuously, such as web servers, online transaction processing systems, and critical infrastructure.

Reduces Risk of System Failures

Soak testing reduces the risk of system failures by identifying and addressing potential issues before the software is deployed to production. This proactive approach helps ensure that the application performs well under real-world conditions.

These benefits make soak testing an essential part of the software development lifecycle, particularly for applications that require high reliability and performance over long periods.

Common Soak Testing Challenges & Their Solutions

The process of soak testing, while highly beneficial, also has its challenges. Here are some common challenges and their solutions:

Resource Constraints

Soak testing requires significant resources, including hardware, software, and time. This can be a constraint, especially for smaller teams or projects with limited budgets. Therefore, prioritize critical components and functionalities for soak testing. Moreover, use cloud-based testing environments to scale resources as needed and reduce costs.

Long Test Duration

The extended duration of soak tests can make it difficult to maintain consistent monitoring and analysis. Therefore, monitoring and data collection processes should be automated. Also, use tools that provide real-time alerts and automated reports to keep track of performance metrics without constant manual oversight.

Data Management

Soak tests generate large quantities of data that can be challenging to manage and analyze. To manage and analyze data effectively, you can use different tools. For example, you can use data visualization tools to help interpret the results and identify trends more easily.

Isolating Issues

A complex system and prolonged test can make identifying the root cause of performance issues difficult. To correlate performance issues with specific events or actions, you should use detailed logging and tracing. Furthermore, you should break down the test into smaller segments to isolate and identify issues more effectively.

Interpreting Results

Interpreting the results of a soak test can be complex, especially when dealing with subtle performance degradations over time. So, use statistical analysis and machine learning techniques to identify patterns and anomalies in the data. You can also collaborate with performance experts to gain deeper insights into the results.

Real World Soak Testing Examples

Soak testing is applied across various industries to ensure the stability and performance of systems under prolonged usage. Here are some real-world examples:

E-commerce Platforms

Major retail websites conduct soak tests on their checkout processes, payment gateways, and inventory systems over several weeks to ensure they can handle the surge in transactions and user activity. This helps prevent crashes and slowdowns during peak shopping periods.

Streaming Services

These platforms perform soak tests to simulate continuous streaming by millions of users. The tests help identify issues like buffering, latency, and server load handling, ensuring a smooth viewing experience for users.

Financial Services

Banks conduct soak tests to handle large volumes of transactions, especially during peak times like salary days or tax filing deadlines. This ensures that their systems can process transactions efficiently without delays or errors.

Cloud Services Providers

Cloud service providers run soak tests to validate the stability and performance of their cloud infrastructure under continuous load. This includes testing virtual machines, storage solutions, and network services to ensure they can support sustained high usage.

Gaming Industry

Popular games like League of Legends or Fortnite perform soak tests to ensure their servers can handle the load of millions of players simultaneously. This helps prevent server crashes and ensures a smooth gaming experience.

Final Thoughts

Soak testing is essential for making sure software can handle long hours of use without breaking down. It helps find problems like memory leaks and resource depletion, improving system stability and user experience. Although soak testing comes with challenges, strategies like automated monitoring and using cloud resources can make it easier.

For development teams planning to incorporate soak testing, providers like Testlio offer powerful solutions that simplify testing efforts. Testlio’s extensive experience and specialized tools enable precise monitoring and effective test management.

Contact us to learn how we can help keep your software reliable and performing well in every scenario.