--- a/SI/lvm.pm	Tue Jan 19 14:49:43 2010 +0100
+++ b/SI/lvm.pm	Tue Jan 19 23:45:54 2010 +0100
@@ -17,10 +17,13 @@
 
     my $devs = shift;
 
+    # find the physical volumes we've already recognised as „non-removable“
+    my @known = keys %{$devs->{volume}}, keys %{$devs->{disk}};
 
-    # find the physical volumes we've already recognised as „non-removable“
-    my @pvs = grep { $_ ~~ $devs->{known} } map { s/\s*//; (split /:/)[0] } `pvdisplay -c`;
-    return @volumegroups = map { (split /:/)[1] } `pvdisplay -c @pvs 2>/dev/null`;
+    my @pvs = grep { $_ ~~ @known } map { s/\s*//; (split /:/)[0] } `pvdisplay -c`;
+    @volumegroups = map { (split /:/)[1] } `pvdisplay -c @pvs 2>/dev/null`;
+    run("vgchange -ay @volumegroups 2>&1 >/dev/null");
+    return @volumegroups;
 }
 
 sub volumes(\%) {
@@ -30,8 +33,6 @@
     # physical devices known to lvm, not just the non-removable
 
     my @vgs = _vgs(%$devs);
-    run("vgchange -ay @vgs 2>/dev/null");
-
     my @lvs = 
 	      map { abs_path ((dirname $_) . "/" . readlink) } 
 	      map { s/^\s*//; (split /:/)[0] }