Traditionally with LVM snapshots you need to be especially careful when choosing how big to make your snapshots; if it is too small it will fill up and become invalid. If taking many snapshots with limited space then it becomes quite difficult to decide which snapshots need more space than others. One approach has been to leave some extra space in the VG and let dmeventd periodically poll and lvextend the snapshot if necessary (I covered this in a previous post ).
