HBase is an open-source non-relational distributed database modeled after Google's Bigtable and written in Java. It is one of the many components of Hadoop. Hadoop is a software framework for storing data and running applications on clusters of commodity hardware.
Hbase is a kind of NoSQL database. A NoSQL database provides a mechanism for storage and retrieval of data that is modeled in means other than the tabular relations used in relational databases. Such databases have existed since the late 1960s, but the name "NoSQL" was only coined in the early 21st century, triggered by the needs of Web 2.0 companies. HBase is column oriented database making it great for the purpose of aggregation. HBase provides a fault-tolerant way of storing sparse data sets, which are common in many big data use cases. One of the remarkable use case is that Twitter uses it for storing and managing its data.