Why would these two commands report free space so differently? This started happening last year on several Ubuntu 18.04 VMs from time to time.
df reports 100% used while
du -smh shows only 2.3G of the 4.0G (total) in use.
This is often followed by
syslog-ng filling up
/var with error messages when the syslog server is down for maintenance.
# df -mh /var Filesystem Size Used Avail Use% Mounted on /dev/mapper/new_vg-var 4.0G 3.9G 0 100% /var # du -smh /var 2.3G /var # fuser /var