To use Hadoop Archives with MapReduce, you must reference files slightly differently than with the default file system. If you have a Hadoop Archive stored in HDFS in /user/ zoo/foo.har, you must specify the input directory as har:///user/zoo/foo.har to use it as a MapReduce input. Since Hadoop Archives are exposed as a file system, MapReduce is able to use all of the logical input files in Hadoop Archives as input.