Hadoop

Hortonworks Data Platform

http://hortonworks.com/

HDFS

See http://hadoop.apache.org/docs/stable/hdfs_user_guide.html.

Overview :

hadoop dfsadmin -report

Rebalance data :

hadoop balancer

Main commands :

hadoop fs             # Main help output
hadoop fs -dus '/*'   # Get size of all root directories (in bytes)

Change replication factor of existing files :

hdfs dfs -setrep -R -w 3 foo

Leave safe mode :

hdfs dfsadmin -safemode leave