How to add or remove swap space
Swap space refers to the portion of the virtual memory which is reserved as a temporary storage location.
Check memory and available space
$ free -mh

$ df -h

Enable the swap file
# create a 2G swap file
$ dd if=/dev/zero of=/myswap bs=1024 count=2048000
# mark the file as swap space
$ mkswap /myswap
# enable the swap file
$ swapon /myswap

Make the swap file permanent
$ echo '/myswap none swap sw 0 0' >> /etc/fstab
Disable the swap space
$ swapoff /var/swap
$ rm /swap
Then you should remove the line includes ‘/swap’ from /etc/fstab