Ubuntu Swap File Setup on VPS (2026): Prevent Out-of-Memory Crashes

When Should You Add Swap?

If your VPS has 1-2 GB RAM, swap can prevent abrupt process kills during bursts. Swap is slower than RAM, but better than crashes, especially for occasional spikes.

Step 1: Check Current Memory and Swap

free -h
swapon --show

Step 2: Create a Swap File

sudo fallocate -l 2G /swapfile
sudo chmod 600 /swapfile
sudo mkswap /swapfile
sudo swapon /swapfile

Verify:

swapon --show
free -h

Step 3: Make Swap Persistent

echo '/swapfile none swap sw 0 0' | sudo tee -a /etc/fstab

Step 4: Tune Swappiness and Cache Pressure

sudo sysctl vm.swappiness=10
sudo sysctl vm.vfs_cache_pressure=50

# persist settings
echo 'vm.swappiness=10' | sudo tee -a /etc/sysctl.conf
echo 'vm.vfs_cache_pressure=50' | sudo tee -a /etc/sysctl.conf

How Much Swap Should You Use?

1 GB RAM VPS: 1-2 GB swap
2 GB RAM VPS: 2 GB swap
4 GB+ RAM VPS: 1-2 GB safety swap usually enough

FAQ

Does swap make my VPS faster?

No. Swap prevents crashes; it does not improve performance. If swap usage is constantly high, upgrade RAM.

Can I remove swap later?

Yes. Use sudo swapoff /swapfile, remove the fstab entry, then delete the file.

Is zram better than swap file?

For some workloads yes, but swap file is simpler and reliable as a default setup across providers.

For full stability, combine swap with resource monitoring and proactive alerts.