Add a swap file quickly and easily Print

Here are simple, step-by-step instructions to create a 1 GB swap file at /swapfile1 on a typical Linux system (e.g., Ubuntu, Debian, or similar distributions). Run these commands as root or with sudo. Ensure you have at least 1 GB of free disk space on the root filesystem (check with df -h /).

1. Create the 1 GB swap file
   Use fallocate (fastest and preferred on modern filesystems like ext4) or dd as a fallback:

   sudo fallocate -l 1G /swapfile1

   If fallocate fails (e.g., "Operation not supported"), use:

   sudo dd if=/dev/zero of=/swapfile1 bs=1M count=1024
   

2. Set secure permissions (critical for security - swap may contain sensitive data):

   sudo chmod 600 /swapfile1
   

3. Format the file as swap:

   sudo mkswap /swapfile1
   

4. Enable the swap file immediately:

   sudo swapon /swapfile1

   Verify it with:

   swapon --show

5. Make it persistent (enable on boot):
   Edit /etc/fstab (backup first: sudo cp /etc/fstab /etc/fstab.bak):
    

   sudo echo "/swapfile1 none swap defaults 0 0" | sudo tee -a /etc/fstab