code: public long getSaving(Configuration conf) {
      try {
        DFSClient dfs = ((DistributedFileSystem)FileSystem.get(conf)).getClient();
        Counters raidedCounters = stateToSourceCounters.get(RaidState.RAIDED);
        long physical = raidedCounters.getNumBytes() +
            parityCounters.getNumBytes();
        long logical = raidedCounters.getNumLogical();
        return logical * dfs.getDefaultReplication() - physical;
      } catch (Exception e) {
        return -1;
      }
    }
docs: Get the saving of this code in bytes
  @return The saving in bytes