You use the hadoop fs –put command to add a file “sales.

The file will remain under-replicated until the administrator brings that node back online

The cluster will re-replicate the file the next time the system administrator reboots the NameNode daemon (as long as the file’s replication factor doesn’t fall below)

This will be immediately re-replicated and all other HDFS operations on the cluster will halt until the cluster’s replication values are resorted

The file will be re-replicated automatically after the NameNode determines it is under-replicated based on the block reports it receives from the NameNodes