Hi Vinay,   Do you see any error in logs while running "reassign partition tool" ? This might help to debug issue. Were all the brokers healthy and ISR were good before you ran the tool?   ***When I ran this tool, it was stuck with one partition and it hung there for more than a day. The Cluster performance was severely impacted, and we had to restart the entire cluster. >> I can suggest if the data/topics are more then probably you can do reassignment of subset of topics to avoid load on the cluster. You can provide a list of topics that should be moved to the new set of brokers and a target list of new brokers.   ***I don't see a way even to stop the tool when its taking long time. >> You can abort the assignment by deleting the "/admin/reassign_partitions" zk node on your zookeeper cluster using zookeeper shell, and move the partitions that are assigned to the dead broker to new nodes.   Thanks Sagar S   ... View more