Introduction
I’m continuing my 30-day Linux challenge as part of my preparation for the RHCSA exam, and today’s topic might just be a lifesaver for system admins and everyday users alike: understanding disk space usage with df
, du
and how to find what’s clogging up your system.
Index
- Why Disk Space Awareness Matters
- What is df
- What is du
- Real Time Scenario
- Industrial Insight
- Recommendations
- Quick Summary
🧱 Why Disk Space Awareness Matters
Running out of disk space can silently break a system whether it's preventing new files from being written, blocking services or even crashing processes. Being proactive is key.
That’s where df
and du
come in, they give you a clear picture of what's full, why, and how to fix it.
🔍 What is df?
df
(Disk Free) reports available and used disk space on file systems.
🔧 Syntax:
df -h
✅ Example:
$ df -h
Filesystem Size Used Avail Use% Mounted on
/dev/sda1 40G 20G 18G 53% /
-
-h
: Human-readable format (MBs, GBs) - Quickly helps you know which partition is getting full
✅ Pro Tip: Use
df -Th
to also show filesystem types like ext4, tmpfs, etc.
📦 What is du?
du
(Disk Usage) shows how much space a directory or file consumes.
🔧 Syntax:
du -sh /path/to/folder
✅ Example:
$ du -sh /var/log
1.2G /var/log
-
-s
: Summary only (don’t dive into subfolders) -
-h
: Human-readable
🛠 Tip: Run
du -sh *
inside a directory to compare which folders are space hogs.
🧰 Real Time Scenario
You log into a server and see alerts about low disk space. You use:
df -h
to check overall usage — /var
is 90% full.
Then:
du -sh /var/*
to locate the culprit — it’s /var/log
.
Then:
sudo du -ah /var/log | sort -rh | head -n 10
to find which specific log files are bloating. You clear old logs or rotate them. Problem solved.
🧠 Industrial Insight
In cloud deployments and containerized environments (like Docker), disk bloat is common. Backups, logs, caches — they add up silently. Keeping df
and du
in your toolbox can save hours of debugging.
🛡️ Recommendations
- 🔁 Set up cron jobs to monitor disk usage weekly
- 📉 Automate cleanup with logrotate
- 🚀 Combine
find
,du
andxargs
to identify and clean files older than X days - 🧪 Always use
-h
in scripts that will be reviewed by humans
✨ Quick Summary
Command | Purpose | Best Option |
---|---|---|
df |
Check disk usage |
df -h or df -Th
|
du |
Folder/file size usage | du -sh |
Today was all about staying in control, disk space issues don’t wait. Now I know exactly what’s filling up my system and more importantly, how to clean it up before it becomes a problem.
I'd love to hear your thoughts, insights or experiences with Linux. Feel free to share and join the conversation [ Connect with me on LinkedIn www.linkedin.com/in/techwithsana ]💜
#30dayslinuxchallenge #redhat #networking #cloudcomputing #cloudengineer #cloudarchitect #cloud #RHCSA #RHCE #RHEL #WomeninTech #Technology
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