Inode in Linux

Let us take a small example where every citizen in European country have a unique personal Identification number. This helps government to track all citizen, helps in documentation. Similar way we have Inodes for all files in linux. During the initial set up of the OS, we define the number of inodes and number of files that is possible in the OS. Inode is a data structure which keeps information of all files like size, user id, group id, permission. But it will not keep information of file name so hard links work fine. We can check inodes with the below command:

[postgres@ip-172-31-28-103 data]$ df -i
Filesystem      Inodes IUsed   IFree IUse% Mounted on
/dev/xvda2     5241840 41618 5200222    1% /
devtmpfs        122059   281  121778    1% /dev
tmpfs           126872     3  126869    1% /dev/shm
tmpfs           126872   337  126535    1% /run
tmpfs           126872    16  126856    1% /sys/fs/cgroup
tmpfs           126872     1  126871    1% /run/user/1000