What Is an Inode and How to Reduce Inode Usage

On Linux, every file and directory takes up one inode in the file system. An inode holds information about a file such as its owner, permissions, timestamps and location on disk. In short, the inode count is the number of files and directories in your account or on your server. An email, an image, a cache file: each one is an inode.

Even if you have free disk space, when inodes run out no new files can be created; your website may show errors and your email may stop arriving.

Checking inode usage

cPanel

In the statistics section on the cPanel home page, the File Usage line shows the number of files and directories (inodes) in your account.

On the server (SSH)

To see inode usage per disk:

df -i

To find the folders with the most files under a directory (in the example, /home):

du --inodes -d 2 /home 2>/dev/null | sort -n | tail -20

How to reduce inode usage

Deleting unneeded files is enough. Large numbers of small files usually pile up in these places:

• Mailboxes: trash, junk (spam) folder and old email. Every email is a separate file.
• Cache directories: files created by the cache plugins of WordPress and similar applications.
• Session and temporary files: application directories such as tmp and sessions.
• Old backups and logs: extracted old backups and growing log directories.

Before deleting, make sure you know what the files belong to; deleting files an application needs can break your website.

The information in this guide is taken from official documentation: GNU coreutils: df, GNU coreutils: du, cPanel: The cPanel Interface.