Administrators can pre-split tables during table creation based on the target number of regions per RegionServer to avoid costly dynamic splitting as the table starts to fill up. In addition, it ensures that the regions in the pre-split table are distributed across many host machines. Pre-splitting a table avoids the cost of compactions required to rewrite the data into separate physical files during automatic splitting. If a table is expected to grow very large, administrators should create at least one region per RegionServer. However, do not immediately split the table into the total number of desired regions. Rather, choose a low to intermediate value. For multiple tables, do not create more than one region per region server, especially if you are uncertain how large the table will grow. Creating too many regions for a table that will never exceed 100 MB in size is not useful; a single region can adequately services a table of this size.
