“du” Reports Less Space Utilization than “df”

Applies to:

Oracle Cloud Infrastructure

Linux x86-64

Symptoms:

The du (/usr/bin/du) and df (/bin/df) commands output display different storage space utilization values:

[opc@instance ~]$ sudo df -k /
Filesystem   1k-blocks    Used Available Use% Mounted on
/dev/sda3      9288792 8672768    144120  99% /
 
[opc@instance ~]$ sudo du -xsk /
2132542    /

In the example above, df reports 8.6 GBs (8672768 KBs) to have been used on the root (/) filesystem, whereas du reports only 2.1 GBs (2132542 KBs) to have been used.

Cause:

The df command reports how many disk blocks are used, whilst du traverses the filesystem and reports the actual number of blocks used (directory by directory), including any space used by existing files.