Rules of thumb involving more swap than RAM probably date from decades ago, when Unix virtual memory systems were sufficiently primitive that the total amount o

Rules of thumb involving more swap than RAM probably date from decades ago, when Unix virtual memory systems were sufficiently primitive that the total amount of virtual memory you could use was just your swap space, not swap space plus (most of) RAM. (The limitation came about because the simple way to handle swapping is to assign every potentially swappable page of virtual memory a swap address when you allocate it in the kernel. Then the kernel always knows that there's space for the page if it ever needs to swap it out and you're never faced with a situation where you need to swap out a page but there's no swap space left.)