In hbase version 0.20.6, If contiguous regions, do not assign adjacent regions in same region server. So it can break daughters of splits in same region server and avoid hot spot. The performance can improve.
In version 0.90.1, daughter is opened in region server that his parent is opened. In the case A region server has thousands of regions. the contiguous region is difficult to Choose by random. So the region server always is hot spot. Should the balance method be choose the contiguous region and then random ? .
