For effectively managing specific usage of different disk hardware types, HDFS offers a Heterogenous Storage Management feature, documented at https://www.cloudera.com/documentation/enterprise/latest/topics/admin_heterogeneous_storage_oview.html. Is that what you are looking for?   The HDFS mover tool available for use with this feature, along with the storage policies that dictate replica placement selection will let you manage the differing hardware better.   If you'd still like to move blocks over manually and not configure the HSM feature, then please read the method and caveat presented under http://wiki.apache.org/hadoop/FAQ#On_an_individual_data_node.2C_how_do_you_balance_the_blocks_on_the_disk.3F ... View more