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.
