Fix High CPU Usage

Identifying High CPU

Check current CPU usage:

top
htop  # More user-friendly
uptime  # Shows load average

Find the Culprit Process

# Show top CPU-consuming processes
ps aux --sort=-%cpu | head -10

# Real-time monitoring
top -c
htop -t  # Tree view

Common High CPU Culprits

1. Web Server (Apache/Nginx)

Check for traffic spikes or misconfigurations:

sudo tail -f /var/log/nginx/access.log
sudo apache2ctl status  # For Apache

Reduce worker processes:

# Nginx
sudo nano /etc/nginx/nginx.conf
# worker_processes auto; -> worker_processes 2;

2. PHP-FPM

sudo systemctl status php*-fpm
# Check pm.max_children setting
sudo nano /etc/php/*/fpm/pool.d/www.conf

3. MySQL/MariaDB

sudo mysqladmin processlist
mysql -e "SHOW FULL PROCESSLIST"

4. Cron Jobs

Check if multiple cron jobs overlap:

grep -r "*/" /etc/cron*  # Find frequent jobs
sudo tail -f /var/log/syslog | grep CRON

5. Malware/Bitcoin Miners

Suspicious processes with random names:

sudo netstat -tunap | grep ESTABLISHED
sudo lsof -i
ps aux | grep -E "minerd|cpuminer|stratum"

Immediate Mitigation

# Kill problematic process (replace PID)
sudo kill -9 PID

# Renice a process (lower priority)
sudo renice +19 -p PID

# Restart the service
sudo systemctl restart servicename

Preventive Measures

• Set CPU limits with cgroups
• Implement CloudLinux or similar
• Upgrade VPS plan if consistently high
• Add monitoring (Netdata, Prometheus)