public ServerName[] getSecondaryAndTertiary(RegionInfo regionInfo, ServerName primaryRS)
    throws IOException {

    ServerName[] favoredNodes;// Get the rack for the primary region server
    String primaryRack = getRackOfServer(primaryRS);

    if (getTotalNumberOfRacks() == 1) {
      favoredNodes = singleRackCase(regionInfo, primaryRS, primaryRack);
    } else {
      favoredNodes = multiRackCase(primaryRS, primaryRack);
    }
    return favoredNodes;
  }
Returns PB'ed bytes of {@link FavoredNodes} generated by the server list.
hbase-balancer/src/main/java/org/apache/hadoop/hbase/favored/FavoredNodeAssignmentHelper.java