Ubuntu 24.04 LTS – inode exhaustion despite free disk space – 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

Writes fail with no space left messages even when df -h shows free capacity.

Environment & Reproduction

Typical with caches creating millions of tiny files.

df -h
df -i
touch /tmp/inode-test

Root Cause Analysis

Filesystem inode table is exhausted by very high file counts.

Quick Triage

Locate directories with extreme file density.

df -i
for d in /var /tmp /home; do echo $d; sudo find $d -xdev -type f | wc -l; done
sudo lsof +L1 | head

Step-by-Step Diagnosis

Rank inode-heavy directories and inspect retention gaps.

sudo find /var -xdev -printf '%h
' | sort | uniq -c | sort -nr | head -n 30
sudo du -xhd1 /var | sort -h
sudo systemctl list-timers --all

Solution – Primary Fix

Purge old cache and temp files that consume inodes.

sudo find /var/tmp -xdev -type f -mtime +7 -delete
sudo find /tmp -xdev -type f -mtime +3 -delete
sudo apt clean

Solution – Alternative Approaches

Move high-churn workloads to filesystems with larger inode pools.

sudo mkdir -p /mnt/data/cache
sudo rsync -a /var/cache/app/ /mnt/data/cache/
sudo mount --bind /mnt/data/cache /var/cache/app

Verification & Acceptance Criteria

Inode usage drops and file creation succeeds.

df -i
touch /var/tmp/inode-ok
rm -f /var/tmp/inode-ok

Rollback Plan

Restore cache backup if application behavior changes.

sudo umount /var/cache/app 2>/dev/null || true
sudo rsync -a /mnt/data/cache/ /var/cache/app/

Prevention & Hardening

Implement periodic cleanup policies for temp and cache paths.

sudo systemctl status systemd-tmpfiles-clean.timer
sudoedit /etc/tmpfiles.d/local.conf
sudo systemd-tmpfiles --clean

Related Errors & Cross-Refs

Often confused with ordinary disk-full incidents.

Related tutorial: View the step-by-step tutorial for Ubuntu 24.04 LTS.

View all Ubuntu 24.04 LTS tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

Linux inode behavior and Ubuntu tmpfiles management guides.