When connected in gateway manager and clicking on details for a given astaro gateway then scrolling down to partition size...
I get for the / partition 1G used whereas when on the astaro box and using df I have exactly:
asg:/root # df /
Filesystem 1K-blocks Used Available Use% Mounted on
/dev/disk/by-label/root
5542276 1474260 3786480 29% /
which is closest to 1.5G:
asg:/root # df -h /
Filesystem Size Used Avail Use% Mounted on
/dev/disk/by-label/root
5.3G 1.5G 3.7G 29% /
thx