I’ve heard of this concept multiple times throughout my time on the internet, but I never understood what causes a “server load”. Now that I’m in one of the biggest instances on Lemmy, this is one of the significant issues that we face. So what is a “server load”, why does it slow down websites instead of stopping them? Does the load on a server increase by the amount of information in it, the browsing of information, or both? Does upvoting and downvoting cause a load too? Does saving posts and comments to your profile also cause a server load?
Similar to when your computer has to do a lot of things at the same time it slows down the machine. A server under load is just a machine that has to process a lot of information at the same time. It does not really matter which operation is performed, but rather the amount of computing power needed to perform it. Sometimes the sheer amount of simultaneous operations can cause load, for example when many users use a service at the same time.
Servers have physical limitations and when those are reached the operating system of that server will try to stay on top of it by scheduling the operations. This will make the server respond slower, since it will first have to fulfill other requests before reaching the newest one. At some point this method will fail, due to physical limitations and timeouts. When a server takes too long to respond because it’s overwhelmed, other services will react with “I’ve waited for x amount of time for a response, I didn’t get one, I will cancel this request.”
To boil it down to one simple statement: The more work has to be done in any given time, the longer each individual piece of work will take to complete on average.