Why are df and du command show inconsistent results?

Question

When I run df -h it shows that 95% has been used in /data4 and I am the only user under /data4.

Filesystem      Size  Used Avail Use% Mounted on
overlay         591G  455G  136G  78% /
tmpfs            64M     0   64M   0% /dev
tmpfs            63G     0   63G   0% /sys/fs/cgroup
/dev/vdb        591G  455G  136G  78% /data
/dev/vdf        591G  537G   54G  91% /data1
/dev/vde        591G  530G   62G  90% /data2
/dev/vdc        591G  556G   35G  95% /data4
/dev/vdd        591G  506G   86G  86% /data3
tmpfs            63G  1.5M   63G   1% /dev/shm
/dev/vda1        99G   82G   13G  88% /etc/localtime
tmpfs            63G   12K   63G   1% /run/secrets/kubernetes.io/serviceaccount
tmpfs            63G   12K   63G   1% /proc/driver/nvidia
devtmpfs         63G     0   63G   0% /dev/nvidia0
tmpfs            63G     0   63G   0% /proc/acpi
tmpfs            63G     0   63G   0% /proc/scsi
tmpfs            63G     0   63G   0% /sys/firmware

However, if I check how much is used in /data4 using du -sh I see this:

pwd
/data4
du -sh
241G 

Only 241G is used. I want to free up space under /data4, but can’t find out where almost more than half of the 556G is used.

Why is that?

Answer 1

You may have run into ext2 and successors reserving 5% of the filesystem for use by the root user.

To set the reserved blocks percentage to 0% (0 blocks):

tune2fs -m 0 /dev/vdc

To get the current value :

tune2fs -l <device>

For more information see the post
Is there a way to make ext-filesystems use less space for themselves in Linux?