Increase swap space

Starting with Ubuntu 18.04, a swap file rather than a dedicated swap partition is used. The swap file is named "swapfile". To modify the size of this swap file:

1. Disable the swap file and delete it (not really necessary as you are going to overwrite it)

   sudo swapoff /swapfile
   sudo rm  /swapfile
   

2. Create a new swap file of the desired size.
   Determine the size of your swap file. If you want to create a 4 GB swap file, you will need to write 4 * 1024 blocks of 1024² bytes (= 1 MiB). This will make your count equal to 4 * 1024 = 4096. Create the file of this size with the command

    

   sudo dd if=/dev/zero of=/swapfile bs=1M count=4096
   

3. Assign it read/write permissions for root only (not strictly necessary, but it enhances security)

   sudo chmod 600 /swapfile
   

4. Format the file as swap:

   sudo mkswap /swapfile
   

5. The file will be activated at the next reboot. If you wish to activate it for the current session:

   sudo swapon /swapfile
   

You can check the available swap with the command swapon -s (no root permissions needed).