diff --git a/plugins/zfs/zfs_usage_ b/plugins/zfs/zfs_usage_
index 07187ee3..fdd5b3a9 100755
--- a/plugins/zfs/zfs_usage_
+++ b/plugins/zfs/zfs_usage_
@@ -160,6 +160,7 @@ sub do_collect {
 
     foreach my $line (split(/\n/, `$fsget` )) {
         my ($name, $key, $value, undef ) = (split(/\t/,$line));
+        ($name =~ s/_/__/g);
         ($name =~ s/\//_/g);
         $filesystems->{$name}->{$key}=$value;
     }
@@ -170,6 +171,7 @@ sub do_config_fs {
     my ($fs) = @_;
     my $fs_slash = ($fs);
     ($fs_slash =~ s/_/\//g);
+    ($fs_slash =~ s/\/\//_/g);
 
     if ( $fs ne $zpool ) {
         printf( "multigraph zfs_usage_%s.%s\n",