Parameters consideration in Map Reduce

1. Speed. The seek times of physical storage is not keeping pace with improvements in network speeds.
2. Scale. The difficulty of scaling the RDBMS out efficiently (i.e. clustering beyond a handful of servers is notoriously hard.)
3. Integration. Today's data processing tasks increasingly have to access and combine data from many different non-relational sources, often over a network.
4. Volume. Data volumes have grown from tens of gigabytes in the 1990s to hundreds of terabytes and often petabytes in recent years.