Este es el formato del comando distcp para copiar de hdfs a hdfs considerando cluster origen y destino en Amazon AWS:

hadoop distcp "hdfs://ec2-54-86-202-252.compute-1.amazonaws.comec2-2:9000/tmp/test.txt" "hdfs://ec2-54-86-229-249.compute-1.amazonaws.comec2-2:9000/tmp/test1.txt"

Mas informacion sobre distcp:

http://www.cloudera.com/content/cloudera-content/cloudera-docs/CDH4/latest/CDH4-Installation-Guide/cdh4ig_topic_7_2.html
http://hadoop.apache.org/docs/r1.2.1/distcp2.html