Monitor Server Disk Space and Send Email Alerts

#!/bin/bash

# --- Configuration ---
THRESHOLD=85 # Percentage (e.g., 85% full)
EMAIL_RECIPIENT="[email protected]"
SERVER_NAME="My Web Server"

# --- Script Logic ---

# Get disk usage for the root partition, excluding snap/loop/tmpfs
# Adjust 'grep -E' pattern if your root partition has a different name
# or you want to monitor specific partitions.
USAGE=$(df -h | grep -E '^/dev/vda1|^/dev/sda[0-9]|^/dev/mapper/' | awk '{ print $5 }' | sed 's/%//g')

# Check if USAGE is empty (no disk found or error)
if [ -z "$USAGE" ]; then
    echo "[$(date)] Error: Could not retrieve disk usage. Exiting."
    exit 1
fi

# Convert USAGE to integer
USAGE_INT=$(echo $USAGE | cut -d'.' -f1)

echo "[$(date)] Current disk usage is $USAGE% on $SERVER_NAME."

if [ "$USAGE_INT" -ge "$THRESHOLD" ]; then
    SUBJECT="ALERT: High Disk Usage on $SERVER_NAME ($USAGE%)"
    BODY="Disk usage on $SERVER_NAME has reached $USAGE%, which is above the threshold of $THRESHOLD%.

Please investigate immediately.

Detailed usage:
$(df -h)"

    echo "[$(date)] Sending email alert to $EMAIL_RECIPIENT..."

    # Make sure 'mail' or 'sendmail' is installed on your system
    # e.g., sudo apt-get install mailutils (Debian/Ubuntu)
    # e.g., sudo yum install mailx (CentOS/RHEL)
    echo -e "$BODY" | mail -s "$SUBJECT" "$EMAIL_RECIPIENT"

    if [ $? -eq 0 ]; then
        echo "[$(date)] Email alert sent successfully."
    else
        echo "[$(date)] Failed to send email alert!"
    fi
else
    echo "[$(date)] Disk usage is within acceptable limits."
fi

echo "[$(date)] Disk monitoring script finished."