HBase

HBase provides a columnar storage. Essentially, it provides a key-value view of the data. The data itself can be organized as column families. Within each column family, the data is stored as byte array with zero or more columns. So, one can have million column rows and still have a low footprint especially, if your data is sparse. Nulls are free. HBase provides random real time read/write access. HBase has a very light schema.