Why does the email disk usage in cPanel not match the disk usage shown with the
Dovecot saves disk space by hardlinking identical messages. When significant hardlinking occurs, the email disk usage reported in the cPanel interface can differ significantly from what you see when using the
du command. The cPanel interface is not hardlink-aware and counts each message as if it were not a hardlink. The
du utility is hardlink-aware and reports the true disk usage by counting the disk usage of the hardlink and not the references. Using the
--count-links option with the
du command will cause
du to count each hardlink as if it were not a hardlink.