Apache HBase (DZone Refcard) by Otis Gospodnetic and Alex Baranau.
From the webpage:
The Essential HBase Cheat Sheet
HBase is the Hadoop database: a distributed, scalable Big Data store that lets you host very large tables — billions of rows multiplied by millions of columns — on clusters built with commodity hardware. Just as Google Bigtable leverages the distributed data storage provided by the Google File System, HBase provides Bigtable-like capabilities on top of Hadoop and HDFS.
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