Basic Resource Monitoring - RamNode Cloud VPS Documentation

Effective server monitoring is essential for maintaining a healthy, performant VPS. This guide covers the fundamental tools and techniques for monitoring system resources on your RamNode VPS, helping you identify bottlenecks, troubleshoot issues, and ensure optimal performance.

Prerequisites

• A RamNode VPS with SSH access
• Root or sudo privileges
• Basic familiarity with the Linux command line

CPU Monitoring

Your CPU is the brain of your server. Monitoring CPU usage helps identify processes consuming excessive resources and potential performance bottlenecks.

Using top

The top command provides a real-time, dynamic view of system processes:

Run top

top

Key metrics to watch in the top header include %us (user CPU), %sy (system CPU), %id (idle), and %wa (I/O wait). Press q to exit.

Using htop

For a more user-friendly interface, install and use htop:

Install and run htop

# Install htop
sudo apt install htop         # Debian/Ubuntu
sudo yum install htop         # CentOS/RHEL

# Run htop
htop

htop displays color-coded CPU bars for each core, making it easy to identify load distribution across your VPS's vCPUs.

Quick CPU Load Check

For a quick snapshot of CPU load averages:

Check load average

uptime

This displays three load averages representing 1, 5, and 15-minute intervals. As a general rule, load average should stay below the number of CPU cores available.

Memory Monitoring

Memory management is critical for server stability. Running out of memory can cause applications to crash or trigger the OOM killer.

Using free

The free command displays memory usage in a simple format:

Check memory

free -h

The -h flag displays values in human-readable format (GB, MB).

Column	Description
total	Total installed memory
used	Memory currently in use by processes
available	Memory available for new applications (includes cache)
buff/cache	Memory used for disk caching (reclaimable)

Finding Memory-Hungry Processes

To identify processes consuming the most memory:

Top memory consumers

ps aux --sort=-%mem | head -10

Disk Usage Monitoring

Monitoring disk space prevents unexpected outages caused by full filesystems, which can crash databases and prevent logging.

Using df

The df command shows filesystem disk space usage:

Check disk space

df -h

Focus on the Use% column. As a best practice, keep disk usage below 80% to maintain performance and leave room for unexpected growth.

Using du

To identify which directories are consuming the most space:

Find large directories

# Show largest directories in /var
sudo du -h --max-depth=1 /var | sort -hr | head -10

# Find large files (over 100MB)
sudo find / -type f -size +100M -exec ls -lh {} \; 2>/dev/null

Disk I/O Monitoring

Use iostat to monitor disk I/O performance:

Install and run iostat

# Install sysstat package first
sudo apt install sysstat      # Debian/Ubuntu

# View I/O statistics
iostat -x 1 5

Watch the %util column—sustained values above 80% indicate disk I/O bottlenecks.

Network Monitoring

Network monitoring helps identify bandwidth usage patterns, potential security issues, and connectivity problems.

Using vnstat

vnstat provides network traffic statistics over time:

Install and use vnstat

# Install vnstat
sudo apt install vnstat  # Debian/Ubuntu

# View traffic summary
vnstat

# View live traffic
vnstat -l

Using iftop

For real-time bandwidth monitoring per connection:

Install and use iftop

sudo apt install iftop
sudo iftop -i eth0

Active Connections

To view current network connections:

Check connections

# List all connections
ss -tuln

# Count connections by state
ss -s

All-in-One Monitoring with vmstat and sar

Using vmstat

vmstat provides a comprehensive system overview:

Run vmstat

# Update every 2 seconds, 10 iterations
vmstat 2 10

Column	Meaning
r	Processes waiting for CPU time
b	Processes in uninterruptible sleep (usually I/O)
swpd	Amount of swap memory used
si/so	Swap in/out—high values indicate memory pressure
wa	CPU time spent waiting for I/O

Using sar for Historical Data

The sar utility (part of sysstat) collects and reports historical performance data:

Enable and use sar

# Enable data collection
sudo systemctl enable sysstat
sudo systemctl start sysstat

# View CPU usage for today
sar -u

# View memory usage
sar -r

# View I/O statistics
sar -d

Quick Reference Commands

Here's a summary of essential monitoring commands for quick reference:

Command	Purpose
top / htop	Real-time process monitoring
free -h	Memory usage overview
df -h	Disk space usage
iostat -x 1	Disk I/O performance
vmstat 1	Overall system health snapshot
vnstat	Network traffic statistics
ss -tuln	Active network connections
uptime	System uptime and load averages

Monitoring Best Practices

Establish baselines: Monitor your server during normal operation to understand typical resource usage patterns before problems occur.

Set up automated monitoring: Consider implementing dedicated monitoring tools for continuous monitoring with alerting.

Monitor logs: Regularly check /var/log/syslog and /var/log/messages for errors and warnings.

Plan for growth: If you consistently approach resource limits, consider upgrading your VPS plan before performance degrades.

Document findings: Keep notes on performance issues and their resolutions for future reference.

Automated Monitoring Solutions

While the command-line tools above are great for quick checks and troubleshooting, for production environments you'll want automated monitoring with dashboards, alerting, and historical data. We have detailed deployment guides for several popular monitoring solutions:

Grafana + Prometheus

Industry-standard monitoring stack with beautiful dashboards and powerful alerting.

Grafana Guide Prometheus Guide

Netdata

Real-time performance monitoring with beautiful dashboards and zero configuration.

Netdata Guide

Uptime Kuma

Self-hosted uptime monitoring with status pages and notifications.

Uptime Kuma Guide

Zabbix

Enterprise-class open source monitoring for networks and applications.

Zabbix Guide

Nagios

Industry-standard infrastructure monitoring with extensive plugin ecosystem.

Nagios Guide

Checkmk

Enterprise-grade monitoring with auto-discovery and comprehensive dashboards.

Checkmk Guide

View all monitoring deployment guides

Next Steps

Now that you understand basic monitoring, consider setting up automated monitoring with alerting. For persistent performance issues or questions about your VPS resources, contact RamNode support for assistance.