One of the more hidden aspects of HBase is how data is actually stored. While the majority of users may never have to worry about it, you may need to get up to speed to learn what the various advanced configuration options at your disposal mean.
"How can I tune HBase to my needs?" and other similar questions are certainly interesting once you get over the (sometimes steep) learning curve of setting up a basic system. Another good reason for wanting to know more is if, for whatever reason, disaster strikes and you need to recover an HBase installation.
During my efforts at getting to know the respective classes that handle the various files, I started to sketch a picture in my head that illustrated the storage architecture of HBase. But while the ingenious and blessed disciples of HBase easily navigate back and forth through that maze, I find it much more difficult to keep a coherent image. So I decided to put that sketch to paper. Here it is: