• Stands for Index Node

  • Essentially an identification number associated with a data structure that contains metadata about a piece of data (like a file or directory) stored on the File System

  • This metadata includes information such as permissions, ownership, timestamps, and pointers to the actual data blocks, but it does not include the data itself or the name of the file or directory

  • In order to have data stored on the Flash Memory, we must have an Inode associated with it, otherwise we will have Inode Exhaustion

  • We can list out the content of the data structure using stat a

  • The data cant be overridden as long as the Hard isn’t 0

Inode Number

  • To uniquely identify a File
# Obtian the inode number
ls -i

Inode Exhaustion

  • We are unable to create new File System even if there is still space on Disk. Because we have no more inode to maintain the metadata of the data piece on the Disk
  • This can happen when we have a lot of small files like cache files
  • This problem can be avoided on ZFS (Zettabyte File System) where Inode is allocated dynamically
# Check the total number inode available & used
df -i