Troubleshooting · Lesson 5 of 26 · 8 minutes

Disk pressure review

Use disk and log size commands in triage.

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Your objectives

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1
Show disk
Run df -h.
Hint & worked example
Inspect the virtual filesystem capacity report. Real systems can run out of space or inodes independently.
The command outcome must match the task, including successful access or the explicitly requested failure.
```
df -h
```
Remember: Available space is a snapshot, not a guarantee that a later write will succeed.
2
Size logs
Run du -sh /var/log.
Hint & worked example
Estimate usage attributed to files or directories; compare it with filesystem capacity when investigating storage.
The command outcome must match the task, including successful access or the explicitly requested failure.
```
du -sh /var/log
```
Remember: du describes file usage, whereas df describes filesystem capacity.
3
Find logs
Run find /var/log -name log.
Hint & worked example
Search directory trees by criteria rather than relying on one shallow listing.
The command outcome must match the task, including successful access or the explicitly requested failure.
```
find /var/log -name log
```
Remember: Quote wildcard patterns so find receives them instead of the shell expanding them first.

Understand the pattern

Junior operators build confidence by gathering evidence before changing systems.

df: Inspect the virtual filesystem capacity report. Real systems can run out of space or inodes independently.
Available space is a snapshot, not a guarantee that a later write will succeed.
du: Estimate usage attributed to files or directories; compare it with filesystem capacity when investigating storage.
du describes file usage, whereas df describes filesystem capacity.
find: Search directory trees by criteria rather than relying on one shallow listing.
Quote wildcard patterns so find receives them instead of the shell expanding them first.

Worked example and expected result

$ df -h

Filesystem      Size  Used Avail Use% Mounted on
lab-root         20G  6.4G   14G  32% /
lab-logs        2.0G  180M  1.9G   9% /var/log

Exit status: 0. The command completed successfully in the training fixture.

$ du -sh /var/log

3K	/var/log

Exit status: 0. The command completed successfully in the training fixture.

$ find /var/log -name log

/var/log
/var/log/auth.log
/var/log/cron.log
/var/log/dpkg.log
/var/log/journal/backup.log
/var/log/journal/nginx.log
/var/log/journal/ssh.log
/var/log/kern.log
/var/log/nginx-access.log
/var/log/nginx-access.log.1
/var/log/nginx-error.log
/var/log/nginx-error.log.1
/var/log/syslog

Exit status: 0. The command completed successfully in the training fixture.

Try a variation

Repeat this workflow in the sandbox with a different scratch filename. Keep the system fixtures unchanged and compare the observed output with your expectation before moving on.

Explain it

In “Disk pressure review”, which interpretation is safe?du describes file usage, whereas df describes filesystem capacity.A command appearing in history proves it completed successfully.A successful first check guarantees that every dependent service is healthy.

Apply it elsewhere

Before adapting the du workflow from “Disk pressure review” to another server, what should you do?Paste the training paths unchanged into production.Skip output inspection whenever the command is familiar.Confirm the current directory, target identity, permissions, and the installed command behavior first.

Keep the momentum.

Complete the lab, then explain and apply the pattern.

Next: Permission denied triage Try an incident drill

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GNU Coreutils manual · GNU Bash manual