Since a couple of years ago, Linux distributions use a swap file (to exchange with Ram memory when it is exhausted or to hibernate the system) instead of a swap partition. If, like I do, instead of clean installing version upgrading is used, it is possible that the system still uses the swap partition. In may case I use Ubuntu and both for the desktop and the laptop computers the first installation was done more than 3 years ago, and afterwards I upgraded the system several times. In this article it is shown how to convert a Swap partition to a a Swap file.
We first disable the swap:
sudo swapoff -a
Next, we create the swap file. The recommended size can be found in the table shown in this link:
The following command will create the swapfile:
sudo fallocate -l 3G /swapfile
This creates a swap file of 3Gb, which has to be adjusted for each system. This creates the file in the root of the system (/) but it can be changed if not enough space is available at this partition.
Next, we restrict the file permisions:
sudo chmod 600 /swapfile
Only "root" will be able to write and read this file. We now dedicate this file to swap:
sudo mkswap /swapfile
Last, we have to assure that the swap file is mounted each time the system starts:
echo '/swapfile none swap sw 0 0' | sudo tee -a /etc/fstab
The only remaining thing to do is to erase the old swap partition and reuse the freed space joining it to another partition or whatever is wanted, which we can do with gparted or any other of the available tools for this.