11.1. What is Swap Space?
Swap space can be a dedicated swap partition (recommended), a swap file, or a combination of swap partitions and swap files.
The size of your swap should be equal to twice your computer's physical RAM for up to 2 GB of physical RAM. For physical RAM above 2 GB, the size of your swap should be equal to the amount of physical RAM above 2 GB. The size of your swap should never be less than 32 MB.
Using this basic formula, a system with 2 GB of physical RAM would have 4 GB of swap, while one with 3 GB of physical RAM would have 5 GB of swap.