Does LVM eats my disk space or does df lie

Hi, On Webmin not display correctly the used and free space on lvm.

for example: the lvm is 100G it used 169M but I not have just 95G free, i have an zip with 161M /dev/mapper/vgserver1-backup 99G 169M 95G 1% /home/backup

if I clean anything on /home/backup, i have just lost+found dir: /dev/mapper/vgserver1-backup 99G 6,5M 95G 1% /home/backup

I upload an iso which have 626M size /dev/mapper/vgserver1-backup 99G 619M 94G 1% /home/backup

somewhere i have lost 2-3G free space.

On LVM management i see: backup vgserver1 100 GB 4.63 GB out of 98.49 GB Mounted on /home/backup as ext4



The free disk space displayed in Virtualmin (on the system information page) is only space used by local mounted filesystems - so space in the VG isn't counted.

Also, free space does not count the 5% usually reserved for the root user.