What is a stress test?

Stress testing is the process of determining the ability to maintain a certain level of efficiency in unfavorable conditions of a computer, network, program or device.

This process may include quantitative tests that are performed in a laboratory, such as measurement of error frequency or system failure. The term also refers to a qualitative assessment of factors such as availability or resistance to denial of service (DoS) attacks. Stress testing is usually done along with a more general performance test.

When conducting stress tests, an adverse environment is intentionally created and maintained. Related actions may include:

1. Run several applications that use many resources in the computer at the same time
2. Try to hack into the computer and use it as a zombie to spread spam
3. Flooding a server with useless e-mail messages
4. Make multiple attempts at the same time to access a website
5. Try to infect viruses, Trojans, spyware or other malware into the system.

The adversity is worsened until the performance level drops below a certain minimum threshold or the system completely stops working. To get the most useful results, the individual elements will be changed one by one. This makes it easy to identify specific weaknesses and vulnerabilities.

For example, a computer may have a lot of memory but the security capabilities are not commensurate. Such a system can run multiple applications simultaneously without a problem, but easily gets into trouble when attacked by hackers.

Stress testing can be time consuming and tedious. However, some stress testers prefer to see a system "crash" under increasingly violent attacks or when changing various factors. Stress testing can provide a means to measure degradation, the ability to maintain a system's limited functionality, even if a large portion of it has been compromised.

When the test process has caused a system failure, the final element of the stress test is to determine the extent or the speed at which a system can recover from an adverse event.