An inode is one file or folder, regardless of its size. Plans limit the total count as well as total disk space, and many accounts hit the inode limit long before they run out of gigabytes.
CHECKING YOUR COUNT
The File Usage figure in the right-hand statistics panel on the cPanel home page shows your current count against your allowance.
WHAT USES THOUSANDS OF INODES
WordPress itself, at roughly 2,000 files for a fresh install. Each theme and plugin, often 500 to 3,000 files each. Every uploaded image, multiplied by the five or more thumbnail sizes WordPress generates. Every individual email message, as each is a separate file. Cache files, which can run into tens of thousands. Session files in a tmp folder.
WHAT HAPPENS AT THE LIMIT
New files cannot be written. Uploads fail, email stops being delivered, and automatic backups stop, usually with confusing error messages that do not mention inodes at all.
REDUCING THE COUNT
Delete unused plugins and themes entirely rather than deactivating them. Clear caching plugin folders. Empty mailbox Trash and Junk, and delete mailboxes you no longer use. Remove unused image sizes with a media cleaner plugin. Empty the .trash folder in File Manager.
