If we have a long service process of balancer, like namenode, datanode, we can get metrics of balancer, the metrics can tell us the status of balancer, the amount of block it has moved,
We can get or set the balance plan by the balancer webUI. So many things we can do if we have a long balancer service process.
So, shall we start to plan the new Balancer? Hope this feature can enter the next release of hadoop.