We cannot be sure of the reasons for this message with the snippet that you have provided. If you notice, the connection is being successfuly set but there is not response from DN. ~~~ java.nio.channels.SocketChannel[connected local=/172.31.15.196:50010 remote=/172.31.1.81:57017] ~~~   It can happen due to various reasons, like, the pipeline is interrupted, there are network congestions at play, the DN disk is not performing well, DN host OS is having issues like kernel soft lockups or just that the DN is too heavily loaded to respond back. You'd have to dig in more into the logs and look for more information.   See the messages logged before the exception you're getting in the DN logs. ... View more