Debian 11 – disk space exhausted in root or /var partition – Fix & Prevention

📖 ~1 min read

Table of contents

1. Symptom & Impact
2. Environment & Reproduction
3. Root Cause Analysis
4. Quick Triage
5. Step-by-Step Diagnosis
6. Solution – Primary Fix
7. Solution – Alternative Approaches
8. Verification & Acceptance Criteria
9. Rollback Plan
10. Prevention & Hardening
11. Related Errors & Cross-Refs
12. References & Further Reading

Symptom & Impact

Services fail, updates stop, and logs cannot be written due to full disks.

Environment & Reproduction

Common in systems with verbose logs, backups, or container layers.

cat /etc/os-release
df -h
du -xh /var --max-depth=1 | sort -h

Root Cause Analysis

Unbounded data growth in logs, caches, or application storage consumes capacity.

Quick Triage

Locate largest directories and identify fast-growing files.

sudo du -xhd1 / | sort -h
sudo find /var -type f -size +500M -ls | head
sudo journalctl --disk-usage

Step-by-Step Diagnosis

Determine whether growth is from logs, packages, or runtime artifacts.

sudo du -xh /var/log --max-depth=1 | sort -h
sudo apt clean
sudo lsof +L1

Solution – Primary Fix

Clean package cache, rotate/vacuum logs, and remove stale artifacts.

sudo apt clean
sudo journalctl --vacuum-time=7d
sudo logrotate -f /etc/logrotate.conf
sudo apt autoremove -y

Solution – Alternative Approaches

Extend logical volume or attach additional storage for persistent growth.

sudo lvextend -r -L +20G /dev/vg0/root
df -h

Verification & Acceptance Criteria

Free space restored above operational threshold and services stable.

df -h
systemctl --failed

Rollback Plan

Restore deleted critical data from backups if accidental removal occurred.

sudo rsync -a /backup/critical/ /var/critical/

Prevention & Hardening

Set retention limits and storage alerts for key mountpoints.

sudo systemctl enable --now cron
# configure monitoring alerts for disk usage

Related Errors & Cross-Refs

Related errors include no space left on device and write failed.

Related tutorial: View the step-by-step tutorial for Debian 11.

View all Debian 11 tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

Debian storage management and log retention best practices.