An elephant keeper tells me his HDFS balancer is slow and he can’t sleep well at night. He asks me if I can help speed it up.
OK, by design the HDFS balancer runs slowly in background, balancing the whole cluster periodically. It’s fine to be slow, I tell him, so that it does not affect the normal cluster activities. Your users submit jobs, copy datas in and out, and operate the cluster for fun, without knowing that a balancer is running in the meantime. So go to sleep and sleep well. Don’t worry about slow balancer.