Allocate Swap Memory

Quick reference on adding swap memory to a Linux VPS.

The issue

My Next.js deploy script got to the npm ci line (clean install) and died with an OOM (Out of Memory) error.

Method 1: Add memory to the Ubuntu disk

My Linode VPS only had 512 MB of swap. I could build the project locally and deploy just the distribution, but I wanted a better long-term fix. Also, 512 MB fills up fast.

Increase it to 2 GB. Create the swap file:

# 1. Create a 2GB swap file
sudo fallocate -l 2G /swapfile

# 2. Secure the file permissions
sudo chmod 600 /swapfile

# 3. Set up the swap area
sudo mkswap /swapfile

# 4. Enable the swap
sudo swapon /swapfile

Edit the filesystem table:

sudo nano /etc/fstab

Append this line so the swap file is mounted and activated on reboot:

• /swapfile: location on the storage drive
• none: the mount point
• swap: the type of filesystem
• sw: mount options (short for swap)
• 0 0: flags that mean don't back it up or scan for errors on boot

/swapfile none swap sw 0 0

Save and verify the swap space:

sudo swapon --show

Method 2: Linode dashboard version

I only realized afterward that I could do this in the Linode dashboard so Linode manages it. That involves a few steps:

1. Power off the Linode so you can resize the disk — three dots (...) at top
2. Resize the disk by 1.5 GB — three dots (...) at top

• Calculate 1.5 * 1024 = 1536
• Subtract from the amount in MB: 25088 - 1536 = 23552
• New Size Calculation: Change 25088 MB to 23552 MB

3. Delete the 512 MB swap disk, and create an empty disk (filesystem: swap, size: 2048, label: 2 GB Swap Image)

• Calculate 2 * 1024 = 2048

4. Boot back up — Power On button three dots (...) at top

Now remove the swap file created in Method 1:

# 1. Turn off the internal swap file so Linux stops using it
sudo swapoff /swapfile

# 2. Delete the actual swap file from your disk
sudo rm /swapfile

# 3. Open the file system table to remove the automatic boot rule
sudo nano /etc/fstab

Remove the line from earlier, /swapfile none swap sw 0 0, and save.

Test:

free -h

Extra: PM2 optimization

If you use PM2 to manage standalone Next.js/Node apps, set a memory cap in ecosystem.config.js:

module.exports = {
  apps: [
    {
      name: "next-app-1",
      script: "server.js",
      cwd: "/var/www/mysite/directory", // path to your standalone build
      max_memory_restart: "150M",
      env: {
        NODE_ENV: "production",
        PORT: 3000
      }
    }
  ]
};

To launch or update all apps using this file, run:

pm2 start ecosystem.config.js
pm2 save