diff -Purp mylvmbackup-0.15.org/mylvmbackup mylvmbackup-0.15/mylvmbackup
--- mylvmbackup-0.15.org/mylvmbackup	2015-09-18 15:42:50.478857055 +0200
+++ mylvmbackup-0.15/mylvmbackup	2015-09-21 15:54:42.247382795 +0200
@@ -823,8 +823,14 @@ sub save_posfile
 sub create_lvm_snapshot 
 { 
   my $params = '';
-  $params = "--size=$lvsize" unless $use_thin_snapshots;
-  my $command= "$lvcreate -s $params --name=$backuplv /dev/$vgname/$lvname";
+  if (!$use_thin_snapshots) {
+    if ($lvsize =~ /%(VG|FREE|ORIGIN)$/) {
+      $params = "--extents=$lvsize";
+    } else {
+      $params = "--size=$lvsize";
+    }
+  }
+  my $command= "$lvcreate --snapshot $params --name=$backuplv /dev/$vgname/$lvname";
   return run_command("taking LVM snapshot", $command);
 }