private static boolean isRegionDir(final FileSystem fs, final Path path) throws IOException {
    Path regionInfo = new Path(path, HRegionFileSystem.REGION_INFO_FILE);
    return fs.exists(regionInfo);
  }
Execute the actual compaction job. If the compact once flag is not specified, execute the
compaction until no more compactions are needed. Uses the Configuration settings provided.
hbase-mapreduce/src/main/java/org/apache/hadoop/hbase/regionserver/CompactionTool.java