Inodes

Each file, folder and email message uses one inode. Shared hosts often cap them, so a site with lots of small files (cache, email, old backups) can hit the limit before it runs out of storage space.

Inode limits are often part of a fair-use policy, so they can apply even on plans sold as 'unlimited'.

Example: a WordPress site keeps years of email in the same account, plus a caching plugin that writes thousands of small files and backups saved on the server. Storage use looks low, but the account reaches its inode limit, and the host blocks new uploads or new email until it's cleared.

Clearing old backups, cache files and email usually fixes it. Keeping backups off the server helps too.

What it means for your price: a low inode limit can push you onto a bigger plan even when you have plenty of storage left. Before you buy, check the limit in the host's terms, especially if you keep lots of email on the same plan.

How to check yours: control panels such as cPanel usually show 'file usage' or 'inodes' in the statistics panel.