Uncorrect users backup folders

I have urbackup server on Ubuntu.

in a web browser, I see backups of users’ Linux computers … but it seems to me that something is wrong with the size, for example:
comp1 - files backup ~139Gb

When I go to the backup server via ssh and look at what this backup consists of, I see:
“path to backup user -sh”:
backup_folder1 - 23Gb
backup_folder2 - 18Gb
backup_folder3 - 22Gb
and folder “current” - 0Gb
when i enter to this folder - isee folder “rootfs” with size 2.1Gb

I cant understand where is the occupied place and how backup files are stored.