diff --git a/db/Node.pm.in b/db/Node.pm.in
index bf0e2b12a886bfe45be43bf9fe44fe0181b132f1..927c7dc063b021ff728d09bfec8660e321def070 100755
--- a/db/Node.pm.in
+++ b/db/Node.pm.in
@@ -1660,7 +1660,8 @@ sub ClearBootAttributes($)
 		"update_accounts=0,ipport_next=ipport_low,rtabid=0, ".
 		"sfshostid=NULL,allocstate='$allocFreeState',boot_errno=0, ".
 		"destination_x=NULL,destination_y=NULL, ".
-		"destination_orientation=NULL,reserved_memory=0 ".
+		"destination_orientation=NULL,reserved_memory=0,".
+		"nonfsmounts=0 ".
 		"where node_id='$node_id'")
 	or return -1;
 
@@ -3234,6 +3235,24 @@ sub Setrtabid($$)
     return Refresh($self);
 }
 
+#
+# Set nonfsmounts for a node.
+#
+sub NoNFSMounts($)
+{
+    my ($self) = @_;
+
+    return -1
+	if (! (ref($self)));
+    
+    my $node_id = $self->node_id();
+    
+    DBQueryWarn("update nodes set nonfsmounts='1' where node_id='$node_id'")
+	or return -1;
+
+    return 0;
+}
+
 #
 # Get the max share count for a node. This is actually the pcvm count
 # from the aux table, but might change someday, I hope.
diff --git a/protogeni/lib/GeniCM.pm.in b/protogeni/lib/GeniCM.pm.in
index a3365fc66266fbb8ee1297c55388b2f1e37112ca..8b27fb8f3aeda3ea408cfbcb4b85a38f3534dab6 100644
--- a/protogeni/lib/GeniCM.pm.in
+++ b/protogeni/lib/GeniCM.pm.in
@@ -3210,6 +3210,16 @@ sub SliverWorkAux($$$$$$$$)
 	# Must do this after mapper has run
 	$node->Refresh();
 
+	if ($MAINSITE && $node->sharing_mode()) {
+	    my $physhost = $node->GetPhysHost();
+	    if (defined($physhost)) {
+		my ($osinfo) = $physhost->RunningOsImage();
+		if (defined($osinfo) && $osinfo->FeatureSupported("xen-host")){
+		    $node->NoNFSMounts();
+		}
+	    }
+	}
+	
 	if (grep {$_ eq $virtual_id} keys(%nodemap)) {
 	    #
 	    # Already in the aggregate, so reuse sliver.