My cluster version hdfs 2.2 stable ( 2 ha namenodes, 10 datanodes). I was command bin/hdfs dfs -setrep -R 2 / ( replication 1 to 2 )
I found that HDFS is actually replicating the under replicated blocks but it works very slowly. HDFS performs the replication about 1 block per second.
I have about 400000 under replicated blocks so it will take about 4 more days. Is there any way to speed it up?