The Importance of Load Testing Your Services
I have seen quite a lot of web services failing on the first day of their launch. I was one of the website owners who faced this situation in the beginning of my web journey where I was overwhelmed by a swarm of visitors and my hosting provided my activities. My case was not at a professional level where downtime can mean humiliation. It is very common for startup businesses to rush things and get their business online in shortest amount of time by skipping the proven and important tests.
No matter how small you are, if you expect your business to grow, you must be prepared on all fronts to serve your visitors and potential customers. To do that, there are a number of stress tests for your web services which highlight upon the areas in your code that need to be optimized to increase your serving capacity.
When we speak of load test or stress test, the first thing that comes to mind is overwhelming your web service with a flood of requests and see how it copes with that. There is nothing wrong in that, but that is not all either. The web service you are dealing with must be able to cope with security attacks that are known to cripple services, making you think that your server is overloaded when it is not. Care must be taken to resist attacks like SYN flood.
At times, I have experienced cases whereby a server gets crippled so badly because of load that it can take days to recover. In these cases, it even becomes impossible to login to your server via SSH and reboot it because it has no capacity to even do that! Such scenarios can happen and preparation must be done to re-route your traffic to a backup web service.
I have also seen a typical attitude among many business owners; if something works, do not mess with it until it breaks down. Well, while that can be quite convenient, that attitude always hurts you and your business pretty hard when it actually breaks down. This is because you did not bother to improve the existing infrastructure be it hardware or software. Making sure that you constantly apply patches and maintain decent hardware (in case you host your own servers) is another step to ensuring that everything is well oiled and running smooth. This will also help you find glitches and bottlenecks in your setup well before it undergoes serious load situations.
It is not just the hardware that can fail in situations of high load. Outdated software and server applications may be running on a single thread. It may also happen that memory leaks may start becoming visible in situations of high load and this can be a huge choke up in your entire setup. Just like your hardware, software applications need to be re-written to take advantage of multiple cores. In case your applications run on server environment, multithreading can be a huge improvement factor.
Often overlooked is the network over which your servers are interconnected. A badly designed network will definitely show its problems during times of heavy load. Make sure your interconnect switches are properly configured in such a way that they don’t overwhelm the network with unnecessary broadcasts although most modern network devices have broadcast storm prevention mechanism.
Each of the points mentioned here is like a specialization, but this article was just to take you over the various possibilities and raise awareness about stress tests.