System Monitoring in FreeBSD using top, ps, and systat

1. Why Bother with Monitoring?

If a server is like a 24/7 coffee shop, then monitoring is the barista who keeps checking the water temperature, bean stock, and who’s been sitting too long without ordering. Without the barista, the shop could burn down or quietly go bankrupt.

In FreeBSD, the best "baristas" come pre-installed: top, ps, and systat. These three tools are free, fast, lightweight, and perfect if you don’t want to install heavy monitoring packages.

 

2. top — Watching the System's "Heartbeat"

To run it, simply type:

top
top -S
top -o cpu

top gives you a real-time overview of processes. The header shows system load, memory usage, swap, and more. Press P to sort by CPU, or M to sort by memory.

Log Output for Analysis:

top -b -n 20 > log.txt

You can run this in a cron job for periodic snapshots:

*/5 * * * * /usr/bin/top -b -n 1 >> /var/log/top.snap

 

3. ps — Static Snapshot of Processes

While top is like watching a live video, ps is like taking a picture. It’s ideal for scripting and quick process checks:

ps aux
ps aux | grep nginx

Example: Show top memory hogs

ps axo pid,comm,rss | sort -k3 -n | tail

This command lists processes with the highest RAM usage, useful when diagnosing slowdowns.

 

4. systat — All-in-One Terminal Dashboard

systat offers various monitoring modes:

systat -vmstat 1
systat -ifstat 1
systat -iostat 1
systat -pf -tcp 1

These modes display live info about memory, CPU, disk I/O, and network stats. Use Ctrl+C to exit, Ctrl+L to refresh.

Reading -vmstat

• us, sy, id: user, system, and idle CPU percentage
• pi/po: page in/out — watch these to monitor memory pressure
• faults: track I/O and system faults

 

5. Daily Monitoring Workflow

1. Start with top to check for anomalies.
2. Use ps to investigate suspicious PIDs.
3. Check systat for disk or network impact.

 

6. Logging for Later Analysis

To collect logs even when you’re asleep:

* * * * * root /usr/bin/top -b -n 1 >> /var/log/top/minutely.log
*/5 * * * * root /usr/bin/systat -vmstat 1 5 >> /var/log/systat/vmstat.log

 

7. Handy Tips & Tricks

• top -U www → filter by user
• ps axww → show full command line
• Press W in top → save display configuration
• Use top -s 1 → refresh every 1 second
• Use top -b in scripts or cron jobs

 

8. Want a GUI?

Prefer visuals? Try:

• htop — colorful, interactive, needs to be installed
• gkrellm — system monitor widget
• netdata — modern web-based dashboard

Monitoring is a form of preventive care. With top, ps, and systat, you have powerful tools to track down performance issues and keep your FreeBSD server healthy.

Get into the habit of checking these tools daily. When your server is happy, you’ll be happy too. Happy monitoring!