🟡 Medium   ⏱ 5–30 min  Last verified: 19 May 2026

📖 ~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

Root filesystem reaches 100% usage and services fail to write state. Package operations, logins, and updates may fail.

Environment & Reproduction

Ubuntu 22.04 hosts with verbose logging or repeated service failures. Reproduce by generating high-volume logs without rotation limits.

Root Cause Analysis

systemd-journald stores persistent logs under /var/log/journal; without sensible caps, sustained error output can exhaust disk space.

Quick Triage

Run df -h and sudo journalctl –disk-usage. Identify largest directories with sudo du -xh /var/log | sort -h.

Step-by-Step Diagnosis

Inspect noisy units using journalctl -p err -b and per-service logs. Review journald config in /etc/systemd/journald.conf.

Illustrative mockup for ubuntu-22-04-lts — ubuntu2204-common-problem-10-diskfull-01.webp
Disk fills rapidly due to oversized systemd journal logs. — Illustrative mockup — Progressive Robot

Solution – Primary Fix

Free space with sudo journalctl –vacuum-time=7d or –vacuum-size=500M, then set SystemMaxUse and RuntimeMaxUse in journald.conf and restart journald.

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Illustrative mockup for ubuntu-22-04-lts — ubuntu2204-common-problem-10-diskfull-02.webp
Vacuum journal and apply retention limits for sustained control. — Illustrative mockup — Progressive Robot

Solution – Alternative Approaches

Forward logs to centralized systems and keep local retention short; tune application verbosity levels.

Verification & Acceptance Criteria

Disk usage returns below threshold, journald obeys configured caps, and core services remain healthy across reboots.

Rollback Plan

Revert journald.conf changes and restart service if retention policy unexpectedly removes needed forensic detail.

Prevention & Hardening

Set log retention baselines, alert on filesystem utilization, and investigate recurring high-volume error sources quickly.

No space left on device, Failed to write entry, apt cannot write to cache.

Related tutorial: View the step-by-step tutorial for Ubuntu 22.04 LTS.

View all Ubuntu 22.04 LTS tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

man journald.conf, man journalctl, Ubuntu logging best practices.

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