Swap or the virtual memory paging mechanism in Linux is an important feature of the operating system. It is crucial for the proper operation of the system, although sometimes it leads to performance decrease. Swapping typically occurs when the physical memory (RAM) of a machine is not enough for all the running processes. When that happens, the operating system takes down some chunks of the RAM (pages) and temporarily writes them on the hard disk to free up some memory. Of course this where the performance cost comes, as the hard disk or even solid state drive is many time slower than the RAM. Besides it’s performance cost, swapping is still a very important process. It allows the operating system to continue it’s normal operation. Read More