Apache HBase is a distributed, non-relational database built to handle very large tables with quick response times. It is a NoSQL type database, which means it is non-relational and does not support the full SQL language for query processing. It is constructed on top of the Hadoop environment and uses HDFS for data storage.

However, unlike HDFS, it has very fast response times and is built for random, real-time read/write access. It does this trick by putting data into indexed files that are then stored in HDFS.

HBase is useful if you have large (in the realm of hundreds of millions of records or higher) datasets and need fast single record lookups.