# Inodes and 'No space left on device'

> What an inode is, how to see inode usage with df -i, and how to find directories with millions of small files.

An inode is the data structure a Unix-style file system uses to store information about a file, such as its owner, permissions, size and where its data lives. Each file uses one inode, and many file systems have a fixed number, so millions of tiny files can cause 'No space left on device' while df -h still shows free space.

## How to see it

'df -i' lists total, used and free inodes per file system. 'ls -i' shows a file's inode number, and 'stat <file>' shows its inode details.

## Typical causes

Session or cache directories of web applications, mail queues, unrotated small log files and build caches can create millions of files.

## Finding the directory

GNU du can count inodes: 'du --inodes -x / | sort -n | tail' lists the directories with the most entries.

## How to fix inode exhaustion

1. Confirm: df -i (IUse% near 100%).
2. Find the directory: sudo du --inodes -x --max-depth=3 / | sort -n | tail -20
3. Check what creates the files before deleting anything.
4. Remove old files of that application with its own tool, or with find, for example: find /path -type f -mtime +7 -delete after a dry run without -delete.

## Cautions

- Always run find without -delete first and read the list.
- The inode count of ext4 is fixed when the file system is created.

## Sources

- [inode(7)](https://man7.org/linux/man-pages/man7/inode.7.html)
- [df(1)](https://man7.org/linux/man-pages/man1/df.1.html)
- [du(1)](https://man7.org/linux/man-pages/man1/du.1.html)
- [find(1)](https://man7.org/linux/man-pages/man1/find.1.html)

Last updated: 2026-10-08
URL: https://raincleaner.eu/wiki/linux/inodes