Managing Swap Space on Your VPS

What is Swap?

Swap is disk space used as virtual memory when physical RAM is full. It prevents out-of-memory crashes but is much slower than RAM.

Check Current Swap

free -h
swapon --show

Create a Swap File

# Create 2 GB swap file
sudo fallocate -l 2G /swapfile
sudo chmod 600 /swapfile
sudo mkswap /swapfile
sudo swapon /swapfile

# Verify
free -h

Make It Permanent

Add to /etc/fstab:

/swapfile none swap sw 0 0

Tune Swappiness

Swappiness (0-100) controls how aggressively Linux uses swap. Lower = prefer RAM.

# Check current value
cat /proc/sys/vm/swappiness

# Set to 10 (good for web servers)
sudo sysctl vm.swappiness=10

# Make permanent
echo "vm.swappiness=10" | sudo tee -a /etc/sysctl.conf

Recommended Swap Sizes

• 1 GB RAM → 2 GB swap
• 2-4 GB RAM → same as RAM
• 8+ GB RAM → half of RAM or 4 GB (whichever is smaller)

Remove Swap

sudo swapoff /swapfile
sudo rm /swapfile
# Remove the line from /etc/fstab