Load vs. Stress Testing: Key Differences

Modern IT systems must be ready for any challenge: from a sharp increase in the number of users to extreme loads that go beyond normal operation. To check their stability and reliability, various types of testing are provided. Among them, load and stress testing plays a key role, which is often confused due to similar goals. However, there are fundamental differences between these methods, and if you are looking for a reliable provider of testing services such as PFLB, it is important to understand this difference.

What Is Load Testing?

The main task of load testing is to check the system’s performance by varying the gradual increase in load from minimum to peak. The maximum allowable value is specified in the settings.
The essence of load testing is to measure the ratio of the resource response and the speed of processing requests from users, i.e. how quickly a tab opens, and the speed of calculations. During such testing, the consumption of server resources is determined, and the test itself begins with a smooth increase in load.
The purpose of load testing is to determine how well an application or site performs its tasks under normal conditions and with an increased number of requests. It is worth noting that load testing creates the expected load from users.
Now let’s consider such a test using an average online store as an example. When designing a resource, we expect that our site should withstand a simultaneous load of at least 4 thousand users. The ideal version of the site’s response in this case should not exceed 3 seconds.
Load testing software creates the above-mentioned load and simultaneously determines the response time. If it is higher than expected, then the server has problems with the growth of traffic, and your online store will slow down.
So, the main differences in load testing:

• it helps to determine the reliability of the site or application;
• it helps to understand the operation of the site or application under load;
• the main parameter for testing is the server response time;
• the system performance is measured depending on the different number of users;
• load testing is a part of stress testing;
• it is carried out according to precisely specified requirements based on a certain number of users, response time, throughput, and some parameters for checking the state of the server/application.

What Is Stress Testing?

Stress and load testing are somewhat similar. But unlike the latter, in the former, the load is emulated over a long period of time, for example, for 2-3 hours.
The purpose of stress testing is to determine the “stress resistance” of the server. Ideally, it should work under any load, even slowly, but work. Even if, for example, 10 thousand users visit your online store at the same time, the online store should not crash.
Another similarity with load testing is that the load is emulated, smoothly starting from the minimum and ending with the maximum value. When a certain indicator is reached, the load stops and the server response speed is measured. The purpose of the stress test is to make sure that despite slow operation beyond the permissible load, the server does not crash, although it works slowly.
On each hosting tariff, resources are not infinite and as the load increases, there will come a point when the server will not be able to process any large number of requests. As a result, when trying to access the site, the corresponding error will pop up.
This is how testers get data on the amount of bandwidth, i.e. how many users the site can simultaneously accept during stress testing.
The main features of stress testing:

• Determining the stability of the server;
• The main goal is to determine the strength limit of the server;
• The target parameter for testing is bandwidth;
• A stress test is a comprehensive test that includes load testing;
• Stress testing is testing for excessive load, including an unexpectedly large number of users.

Differences Between Load And Stress Testing

Many people use the terms “stress testing” and “load testing” as synonyms, believing that they mean the same thing. This is not entirely true. Yes, load and stress testing have some common features, such as a smooth increase in load. But in fact, both concepts are two different processes.
Load testing is an increase in load to a peak value at which the system begins to slow down. The essence of stress testing is the constant overload of the resource until the server completely crashes.
Stress testing shows the response speed of your resource when the load significantly exceeds the norm specified in the project requirements.
Is it necessary to conduct a stress test? If you allow the expansion of the user base, then stress testing is necessary. It will show the behavior of the site with a sharp increase in traffic. It is extremely important that the resource works, even if the load is significantly greater than the server’s stability. Otherwise, the loss of customers cannot be avoided. Therefore, when purchasing a hosting plan, take into account the growth of traffic.

What is Performance Testing?

There is another type of testing that is worth knowing about to avoid confusion. This is performance testing.
Software performance is a very important aspect and should be tested at various levels. This type of testing allows the team to determine the performance of the system under normal load, specifically the speed, scalability, and reliability of the system under various loads. This is a very important stage of software validation.
During a performance test, a normal load is applied to the system. Passing this test is necessary to verify the behavior of the system under normal load. The load limit is maintained both above and below the breakout threshold.

Wrapping it Up

Load and stress testing plays an important role in maintaining the stability and performance of modern systems. Load testing helps to determine the limits of operation under normal conditions, while stress testing focuses on analyzing the behavior of the system under critical overloads. If you are interested in conducting such types of testing and are looking for a reliable provider, we recommend paying attention to PFLB. PFLB company has over 10 years of experience in testing IT products using the best tools.