No space left on device — how to fix
write error: No space left on deviceQuick fix: Run df -h to find the full filesystem and df -i to check inodes. Then find big folders with sudo du -xh / --max-depth=2 | sort -h | tail -20 and clean up (journal: sudo journalctl --vacuum-size=200M).
What it means
The kernel couldn't write because the filesystem has no free blocks, or no free inodes (one is needed per file).
Step 1: which filesystem is full?
df -h # space
df -i # inodes
Step 2: find what's big
sudo du -xh / --max-depth=2 2>/dev/null | sort -h | tail -20
Then drill into the biggest folder. ncdu (sudo apt install ncdu) does the same interactively.
Usual suspects and safe cleanups
| Where | Clean with |
|---|---|
systemd journal (/var/log/journal) |
sudo journalctl --vacuum-size=200M |
old logs (/var/log/*.gz, *.1) |
sudo find /var/log -name "*.gz" -delete |
| apt cache | sudo apt clean and sudo apt autoremove --purge |
| snap old revisions | sudo snap set system refresh.retain=2 |
| Docker | docker system prune -a (see the Docker page) |
your caches (~/.cache, pip, npm) |
rm -rf ~/.cache/pip, npm cache clean --force |
df says full, du can't find it
A deleted file that a process still has open keeps using space until the process exits:
sudo lsof +L1 | sort -k7 -n | tail
Restart the process holding it (often a log writer). Truncating instead of deleting avoids this in the future: : > big.log.
Space can also hide under a mount point (files written to /mnt/data before the disk was mounted there).
Out of inodes
df -i at 100% means too many small files. Find folders with the most files:
sudo find / -xdev -type f | cut -d/ -f2-3 | sort | uniq -c | sort -n | tail
Typical culprits: PHP session files, mail queues, cache folders, node_modules copies.
Reserved blocks
ext4 reserves 5% for root by default, so normal users can hit "full" earlier. On large data disks you can lower it: sudo tune2fs -m 1 /dev/sdX1.
Last updated 2026-10-27.