How to use a file as a swap memory ?

When the physical memory of the system (RAM) is full, swap memory is used. Swap memory is created at the time of operating system installation. We can later use a file as a swap memory. We need to first create a file.

dd if=/dev/zero of=/swapfile bs=1024 count=65535

This will create a 64Mb of swapfile. To create more larger swap file increase count value. count can be calculated as (count= ‘block size’ * ‘file size in Mb’).

sudo mkswap /swapfile
sudo swapon /swapfile

To check if swapfile is active or not run the command,

swapon -s