On Sat, Aug 23, 2014 at 8:20 PM, Yatong Zhang <blueflycn@gmail.com> wrote:
 I am using leveled compaction and I changed the replication factor from 3 to 2, but after a few days the disk space weren't freed. I tried to trigger the compaction or clean up, but looks like it didn't take any effect.

nodetool cleanup

Is for the case where your nodes are no longer responsible for ranges they used to be responsible for, as in reducing replication factor.