Apache HBase describes itself as “the Hadoop database,” which can be a bit confusing, as Hadoop is typically understood to refer to the popular MapReduce processing framework. But Hadoop is really an umbrella name for an entire ecosystem of technologies, some of which HBase uses to create a distributed, column-oriented database built on the same principles as Google’s Bigtable. HBase does not use Hadoop’s MapReduce capabilities directly, though HBase can integrate with Hadoop to serve as a source or destination of MapReduce jobs.
via Review: HBase is massively scalable — and hugely complex | Big Data – InfoWorld.