Activate and Configure ZSWAP Automatically

activate_zswap.sh

#!/bin/bash

# zswap Setup Script
# Example: curl -sL https://gist.githubusercontent.com/cnmoro/f7b8935736150dbac4d754051dc07e4b/raw/6c3489e2d612756acddb5152a136484a816b6528/activate_zswap.sh | sudo bash -s 4

set -e

# Check if running as root
if [ "$EUID" -ne 0 ]; then 
    echo "Error: This script must be run as root (use sudo)"
    exit 1
fi

# Check if size parameter is provided
if [ -z "$1" ]; then
    echo "Error: Please provide swap size in GB as parameter"
    echo "Usage: $0 <size_in_gb>"
    echo "Example: $0 4"
    exit 1
fi

SWAP_SIZE="$1"

echo "==================================="
echo "zswap Setup Script"
echo "==================================="
echo "Swap Size: ${SWAP_SIZE}GB"
echo "==================================="
echo ""

# Step 1: Create or recreate swap file
echo "Step 1: Setting up swap file..."

# Check if swap file exists
if [ -f /swapfile ]; then
    echo "Existing /swapfile found. Removing it..."
    swapoff /swapfile 2>/dev/null || true
    rm -f /swapfile
    echo "Old swap file removed."
fi

# Check if swap is already active
if swapon --show | grep -q '/swapfile'; then
    echo "Deactivating existing swap..."
    swapoff /swapfile
fi

# Create new swap file
echo "Creating ${SWAP_SIZE}GB swap file..."
fallocate -l ${SWAP_SIZE}G /swapfile
chmod 600 /swapfile
mkswap /swapfile
swapon /swapfile

# Add to fstab if not already present
if ! grep -q '/swapfile' /etc/fstab; then
    echo '/swapfile none swap sw 0 0' | tee -a /etc/fstab
    echo "Swap file added to /etc/fstab"
else
    echo "Swap file already in /etc/fstab"
fi

echo "Swap file created and activated."
echo ""

# Step 2: Configure GRUB
echo "Step 2: Configuring GRUB..."

# Backup grub config
cp /etc/default/grub /etc/default/grub.backup

# Update GRUB_CMDLINE_LINUX_DEFAULT
if grep -q "^GRUB_CMDLINE_LINUX_DEFAULT=" /etc/default/grub; then
    # Remove any existing zswap parameters
    sed -i 's/ zswap\.[^ ]*//g' /etc/default/grub
    
    # Add zswap parameters
    sed -i 's/^\(GRUB_CMDLINE_LINUX_DEFAULT="[^"]*\)"/\1 zswap.enabled=1 zswap.compressor=lz4 zswap.max_pool_percent=50 zswap.zpool=z3fold"/' /etc/default/grub
    
    echo "GRUB configuration updated."
else
    echo "Warning: GRUB_CMDLINE_LINUX_DEFAULT not found in /etc/default/grub"
    echo "You may need to add it manually."
fi

# Update GRUB
echo "Updating GRUB..."
update-grub

echo ""

# Step 3: Configure initramfs modules
echo "Step 3: Configuring initramfs modules..."

# Add modules if not already present
for module in lz4 lz4_compress z3fold; do
    if ! grep -q "^${module}$" /etc/initramfs-tools/modules 2>/dev/null; then
        echo "$module" >> /etc/initramfs-tools/modules
        echo "Added $module to initramfs modules"
    else
        echo "$module already in initramfs modules"
    fi
done

# Update initramfs
echo "Updating initramfs..."
update-initramfs -u

echo ""
echo "==================================="
echo "zswap setup completed successfully!"
echo "==================================="
echo ""
echo "Please reboot your system for changes to take effect:"
echo "  sudo reboot"
echo ""
echo "After reboot, verify zswap is active with:"
echo "  cat /sys/module/zswap/parameters/enabled"
echo "  (Should display 'Y')"
echo ""
echo "Check swap status with:"
echo "  free -h"
echo "  swapon --show"
echo "==================================="