An inode is a record in a disk table which contains information about a file/folder such as its size and owner.

The number of inodes you use represents the number of files/folders you have on your web hosting account.

SiteGround customers can see the number of inodes they are using from their cPanel > Inodes Usage.

When a file is opened, the file's inode is read by the kernel. The more files/folders you have, the more inodes you use. And the more inodes you use, the more system resources your account consumes.

This is why the number of inodes on a file system is limited. If you run out of inodes, your account may be excluded from the backup system or may even be suspended.

Information on how to reduce the number of inodes your account uses can be found in this article.