Website load stress testing

What is load stress testing?

There are three main terms for website load stress testing by simultaneously acting multiple users (real or simulated): performance, load and stress testing.
All performance and load stress testing require workload definition as part of the test. It may be no load, minimal, normal, above normal or extreme.
So we will use term load stress testing as a general category for all types of website testing by simultaneously acting multiple users. And definition for load stress testing is:

"Any type of website testing where realistic (or hyper-realistic) workloads are characterized, simulated and submitted to the system under test."

Extreme loads are used in load stress testing - to find the breaking point and bottlenecks of tested system.

Normal loads are used in performance testing - to ensure acceptable level of performance characteristics like response time or request processing time under estimated load.

Minimal loads are usually used in benchmark testing - to estimate user experience.

Anyway, load stress testing, not performance, is the shared characteristic across all these types of website testing.
In load stress testing you should trying to break the application by an extreme load and expose bugs that are likely to appear under stress, such as data corruption, buffer overflows, poor handling of resource depletion, deadlocks, race conditions, etc.
The fact that performance metrics such as response time can be measured during load stress testing is practically irrelevant to the purpose of load stress testing. So stress testing and performance testing has a totally different goals, which make it clear that load stress testing is not a species of performance testing.

Another reason for putting performance and stress under load testing is another type of testing known as background testing. In background testing you use workloads (usually normal) to exercise the system under test while you run functional and/or regression tests against the system. The goal of background testing is to test functionality in more realistic conditions, i.e., with a realistic background workload, like it will have in production.

But some sources treat Performance testing as a general category instead of Load testing. This approach is oriented on test results (test measures timings) while the using of Load testing as a category is concentrated on test nature. We do not follow this approach but it rather widespread so it should be mentioned.

For example Rational Unified Process defines these terms as follows :
Performance testing is a class of tests implemented and executed to characterize and evaluate the performance related characteristics of the target-of-test such as the timing profiles, execution flow, response times, and operational reliability and limits.

Included within this class are :

Load testing - Verifies the acceptability of the target-of-test's performance behavior under varying operational conditions (such as number of users, number of transactions, etc.) while the configuration remains constant.

Stress testing - Verifies the acceptability of the target-of-test's performance behavior when abnormal or extreme conditions are encountered, such as diminished resources or extremely high number of users.

Briefly:

• Performance testing is the overall process,
• Load testing checks that the system will support the expected conditions,
• Stress testing tries to break it

If you want to learn more about website load stress testing tool Testing Master, see Product section.

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if you want to know more terms concerning website testing, please go to our Glossary section.