How to set up swap space on Linux

Swap space extends your server's available memory by using disk space as virtual RAM. This is especially useful on servers with little RAM.

1. Check the current swap:
sudo swapon --show
free -h

2. Create a swap file (e.g. 2 GB):
sudo fallocate -l 2G /swapfile
sudo chmod 600 /swapfile
sudo mkswap /swapfile
sudo swapon /swapfile

3. Make it permanent:
Add the following line to /etc/fstab:
/swapfile none swap sw 0 0

4. Adjust swappiness (optional):
The default value is 60. For servers, we recommend a lower value:
sudo sysctl vm.swappiness=10

To make it permanent, add to /etc/sysctl.conf:
vm.swappiness=10