Jim, The HDFS balancer presently does not look at the disks of a DN. They only view DNs on the whole (sum of all usage). The improvement to balance disks of a single DN is trackable at https://issues.apache.org/jira/browse/HDFS-1312
You may balance your disks out manually, however: http://wiki.apache.org/hadoop/FAQ#On_an_individual_data_node.2C_how_do_you_balance_the_blocks_on_the_disk.3F On Fri, May 18, 2012 at 5:54 PM, Jim Donofrio <donofrio...@gmail.com> wrote: > Lets say that every node in your cluster has 2 same sized disks and one is > 50% full and the other is 100% full. According to my understanding of the > balancer documentation, all data nodes will be at the average utilization of > 75% so no balancing will occur yet one hard drive in each node is struggling > at capacity. Is there any way to run the balancer just on a datanode to > force each disk to be 75% full? > > Thanks -- Harsh J
