> > When the snap shot volume is mounted, yes you can do df on it. But > that shows you the state of the volume you take the snapshot of at > the time of the snapshot. That's not what I want to know. > Sorry to answer my own question, but I just learned, lvdisplay shows the amount currently used by the snapshot #lvdisplay /dev/vg_data/lv_backup --- Logical volume --- LV Name /dev/vg_data/lv_backup VG Name vg_data LV UUID B0F6Gw-iVTt-jJ38-nFny-B2lF-QWei-hqJNlT LV Write Access read/write LV snapshot status active destination for /dev/vg_data/lv_data LV Status available # open 1 LV Size 812.89 GB Current LE 208100 COW-table size 143.45 GB COW-table LE 36724 Allocated to snapshot 0.00% <<<<<-------- Snapshot chunk size 8.00 KB Segments 1 Allocation inherit Read ahead sectors 0 Block device 253:1 Tony