https://community.cloudera.com/t5/Support-Questions/Multiple-datanodes-on-the-same-machine/m-p/66256#M48405 <P>Hadoop wasn't designed to run multiple DataNodes on a single host and is prohibited by Cloudera Manager.&nbsp; &nbsp;</P><P>&nbsp;</P><P>The reason for a single DataNode per host is to prevent data loss.&nbsp; Using the default replication factor of 3, every block in a file will be replicated to 3 different hosts.&nbsp; &nbsp;If a host containing a block replica were to go down, the NameNode will mark the block as under-replicated.&nbsp; A new copy of the block will be created on another DataNode bringing the number of replicas back to 3.&nbsp;&nbsp;</P><P>&nbsp;</P><P>If you do not care about data integrity my suggestion is to set the replication factor to 1 or use virtual hosts.&nbsp;</P> Wed, 11 Apr 2018 18:14:20 GMT denloe 2018-04-11T18:14:20Z