Introduction#
The infamous “No space left on device” error in Linux can appear even when the disk looks like it has free space.
This error is extremely common across servers, homelabs, containers, CI pipelines, and production systems.
In this guide, we break down the 10 most common causes—and how to fix each one.
1. The Disk Is Actually Full#
Check Disk Usage#
df -h
Look for partitions at 100% usage.
Fix#
- Clean logs (see section 3)
- Remove old backups, cache, temp files
- Move large data to another volume
2. Inodes Are Full (Even If Disk Space Is Not)#
Linux tracks files using inodes.
When inodes are exhausted, you cannot create new files even if you have plenty of disk space left.
Check inode usage#
df -i
If it shows 100%, that’s the cause.
Fix#
Find directories with huge numbers of tiny files:
sudo find / -xdev -type d -exec sh -c 'printf "%10s %s
" "$(ls -1A "$1" | wc -l)" "$1"' sh {} \; | sort -n
Then clean the culprit directory.
3. Log Files Grew Out of Control#
Typical locations:
- /var/log/syslog
- /var/log/messages
- /var/log/journal/
Check largest logs#
sudo du -sh /var/log/*
Fix#
sudo truncate -s 0 /var/log/syslog
sudo systemctl restart rsyslog
For journald:
sudo journalctl --vacuum-size=200M
4. Docker Consuming All Disk Space#
Check Docker disk usage#
docker system df
Clean unused images & containers#
docker system prune -a
docker volume prune
5. Snapshots Filling Storage (ZFS, Btrfs, LVM)#
Check ZFS usage#
zfs list -t snapshot
Remove snapshots:
sudo zfs destroy tank/data@snap1
Check Btrfs usage#
sudo btrfs filesystem usage /
6. A Mounted Volume Is Full#
Check mounts#
mount | column -t
If the target mount is full, you get the error even when / has free space.
7. Tmpfs or /tmp Is Full#
Check#
df -h /tmp
Fix#
- Clear /tmp
- Increase tmpfs size in /etc/fstab
8. A Process Holding Deleted Files#
Check open deleted files#
sudo lsof | grep deleted
Fix#
Restart the relevant service:
sudo systemctl restart <service>
9. Quotas Reached#
Check quotas#
sudo repquota -a
Fix#
sudo edquota <username>
10. Wrong Partition Used Due to Missing Mount#
If a mount fails, applications may write to the underlying root filesystem.
Check#
mount | grep /data
Conclusion#
The “No space left on device” error can come from many different sources—not just lack of space.
By checking disk usage, inodes, logs, mounts, Docker, and snapshots, you can diagnose and fix it quickly.
Need Help?#
If your business relies on Linux systems and you want professional support:
👉 TechZ — We solve Linux problems.
https://techz.at
We help with:
- Storage issues
- Production incidents
- Filesystems (ZFS, LVM, ext4, Btrfs)
- Docker & Kubernetes
- Automation & DevOps
Reach out anytime.