Performance: Capacity Vs Stress Vs Soak Vs FailoverTesting

Capacity testing, Stress testing, Soak Testing and Failover testing are types of performance testing that aim to evaluate the behavior of a system under different load conditions, but they focus on different aspects of the system's performance.

e.g. once the linear relationship between increasing load which increase system thruput break down i.e. when we reach saturation we are in the realms of stress testing. While the linear relationship exists i.e. acceptable performance that zone is where we are at capacity. The max capacity is the point before which linear relationship breaksdown.

Capacity Testing

Capacity testing is a type of performance testing that involves determining the system's capacity to handle a specific amount of load while maintaining acceptable performance. It is used to identify the upper limits of a system's scalability and ensure that the system can handle the expected load without degradation of performance. In capacity testing, you gradually increase the load until you reach the maximum number of users or transactions the system can handle without breaking down. The goal is to find out how many users or transactions the system can support while still meeting performance targets.

Stress Testing

Stress testing is a type of performance testing that focuses on evaluating a system's stability and robustness by subjecting it to extreme or unrealistic conditions. The purpose of stress testing is to identify the breaking point of a system, where it fails or becomes unstable. Stress tests often involve scenarios where resources are insufficient, such as excessive load, limited memory, or network disruptions. The goal is to understand how the system behaves under extreme conditions and whether it can recover gracefully from failures.

Soak Testing

Soak testing, also known as endurance testing, involves subjecting a system to a consistent load over an extended period of time to evaluate how it performs under sustained usage. The goal of soak testing is to identify memory leaks, resource leaks, and performance degradation that might occur when a system is running for an extended duration. This type of testing is particularly useful for identifying issues that arise over time due to memory consumption or other factors.
Example: Running a web application with a consistent number of users performing typical actions for several hours to detect any memory leaks or performance degradation that might occur over time.

Failover Testing

Performance failover testing is a type of testing that assesses a system’s behavior when transitioning from a primary system to a secondary system (failover) in response to a failure or downtime. This testing ensures that the failover process is smooth and doesn’t negatively impact the system’s performance. The goal is to validate that the backup or secondary system can handle the expected load and maintain acceptable performance levels during and after the failover event.
Example: Simulating a network or hardware failure on the primary server and monitoring the response time and stability of the secondary server during the failover process.

In summary, while capacity testing, stress testing, soak testing and failover testing involve applying load to a system to assess its performance, they have different goals:

- Capacity testing aims to determine the system's maximum capacity under normal load conditions and ensure that it meets performance targets.
- Stress testing aims to identify the system's breaking point and evaluate its behavior under extreme conditions.

- Performance Failover testing evaluates the system’s ability to transition from a primary to a secondary system during failure scenarios while maintaining performance.
- Soak testing evaluates a system’s stability and performance over a longer duration to identify issues that might arise due to sustained usage, such as memory leaks.

These types of testing are important in ensuring that a system can handle varying levels of load and stress while maintaining acceptable performance and reliability.