Oracle Linux Basic Administration Series - Part 7 - How to Monitor System Performance in Oracle Linux

Monitoring system performance is one of the key responsibilities of a Linux administrator.It helps you understand how your server is performing, detect bottlenecks, and troubleshoot issues before they become serious problems.

In this blog, you’ll learn how to use essential command-line tools to monitor CPU, memory, disk, and process activity on Oracle Linux.

Step 1: Check System Uptime and Load

To quickly see how long your system has been running and how busy it is:

uptime

Example output:

• load average → system load in the last 1, 5, and 15 minutes.A load value near the number of CPU cores means your system is busy but stable.

  
  

Step 2: View Real-Time System Stats with top

top gives you a live view of system activity.

Run:

top

Key sections:

• Tasks: number of running and sleeping processes

• %Cpu(s): CPU utilization by user/system/idle time

• KiB Mem: memory usage

• COMMAND: list of processes using the most resources

Quit with q.

Step 3: Check Memory Usage with free

To check memory and swap usage:

free -h

Output:

Step 4: View CPU and I/O Statistics with vmstat

vmstat (Virtual Memory Statistics) provides an overview of CPU, memory, and process usage.

Example:

This shows updates every 5 seconds, five times.

Columns:

• r: running processes

• b: blocked processes

• us: user CPU time

• sy: system CPU time

• id: idle time

• wa: I/O wait

Step 6: Monitor Disk Usage and Space

View overall disk space:

df -h

Check directory size:

du -sh /var/log

List top 10 largest files/directories:

sudo du -ah / | sort -rh | head -n 10

Step 7: Monitor Disk I/O with iostat

To install and use iostat:

sudo dnf install -y sysstat
iostat -xz 5

Key columns:

• tps → transactions per second

• kB_read/s, kB_wrtn/s → read/write speed

• %util → how busy the disk is (over 80% may indicate I/O bottleneck)

Step 8: Monitor Network Activity

Check network interface statistics:

ip -s link

Step 9: Check System Logs

Logs are essential for troubleshooting performance issues.

View system logs:

sudo journalctl -xe

Check boot logs:

sudo dmesg | less

Step 10: Monitor System Performance Over Time with sar

sar collects, reports, and saves performance data. It’s part of the sysstat package.

To start data collection:

sudo systemctl enable --now sysstat

Check CPU usage history:

sar -u 5 3

Check memory usage:

sar -r 5 3

Conclusion

You’ve now learned how to monitor system performance and resources in Oracle Linux using both built-in and enhanced tools.

These commands are your first line of defense in diagnosing system slowness or resource issues.

Next, we’ll move into disk management - learning how to create, format, and mount partitions and file systems.