#4 Mongo DB:

Developed by the founders of DoubleClick, MongoDB formulates implementation of data in certain applications faster, as it stores data in the form of JSON like documents that are coalesced with dynamic schemas. This database has all the key features for a NoSQL database like key-value storage, JavaScript formatting, and flexible replication for sharding across nodes. Currently enterprises like MTV Networks, Craigslist, Disney Interactive Media Group, The New York Times and Etsy utilize Mongo DB technology. MongoDB is available under GNU General Public License, with language drivers available under Apache License.

#3 Hadoop (HBase):

Hadoop, one of the biggest tools in database, has its own data store called HBase. This database primarily runs in an open source technology which supports NoSQL data stores. HBase uses Hadoop Distributed File System (HDFS). The HDFS is designed to be a non-relational columnar distributed database. The mapping structure of Hadoop is well-suited for complicated computational jobs and queries.

In 2010, Facebook acquired HBase to provide fault-tolerance storage to their databases. This acquisition gave them access to large quantities of spare data. Apache HBase is available under Apache License 2.0.

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