Creating and enabling swap (mkswap, swapon, swapon --show) and making it persistent

Swap is disk space the kernel uses as overflow for memory. When RAM fills up, the kernel moves pages that have not been touched recently out to swap so active programs can keep running. Swap is much slower than RAM, so it is a safety net rather than a performance feature, but many workloads and the RHCSA exam expect you to add it on request. Swap can live on a partition, on a logical volume or in a file; exam tasks usually ask for a partition or a logical volume of a given size.