Hi @aawasthi, I know it has been a while since you asked this question, but I ran into a similar issue, and it can be caused by many things. What I would do in your case is to check if there is some firewall between the 2 datanodes (you can try with telnet), and if there isn't, try checking the number of *_wait connections on the source datanodes. I have found that some of the replicas for what I was trying to copy were placed on a datanode which was technically working, but had a lot of connections in a close_wait state, which were using the overall limits. Feel free to take a look at the answer below: https://community.hortonworks.com/questions/38822/hdfs-exception.html#answer-38817 and the one below that, if you need more details. I hope it helps, camypaj ... View more