Having your website load quickly is important for a number of reasons. Poor performance could cost you visitors by driving them away and lowering your search result rankings. In order to determine if your website is performing satisfactory and able to handle the traffic it gets you need to run load and stress tests.
Running load tests let you realize your server's capability by simulating users and getting back performance results. Virtual users in the software act like real users and simulate user actions to determine the system's speed and endurance. Performance results are reported at the end with possible suggestions to improve.
Load tests are more practical than hiring a bunch of people to test as they are run by scripts and act as people at a far faster rate. It wouldn't be practical or cost efficient to hire people, as the software can act as many people simultaneously for much cheaper.
In order to test the endurance of your system, you need to run an endurance test. An endurance test simulates an average load of users over an extended period of time. The test uses a fixed number of users and is supposed to simulate the system's average stress.
A stress test is useful for benchmarking your system and for finding any bottlenecks it may have. A stress test consists of a series of load test which systematically increase over a duration of time. Raising the load over time allows you to pinpoint the system's limitation and find its optimal range.
It is important that the load generators are powerful enough to simulate the required amount of virtual users, and to have the capacity to send all of the required data. Load generators are the computers used to simulate users. Having enough computers that are strong enough is important for accurately simulating your system's traffic.
The key bits of information to get from performance results are response time, latency, and maximum amount of concurrent users. Knowing this information allows you to determine if your current system setup is performing optimally for the traffic it gets. Having your site load quickly is crucial for retaining users and having better search results in search engines.