This is the layer where all of the data is stored in the form of files. These files are internally split by the Hadoop system into multiple parts and replicated across the servers for high availability.
Since we are talking about the data stored in terms of files, it is very important to understand how these files are organized for better governance.
The next diagram shows how the data can be organized in one of the Hadoop storage layers. The content of the data can be in any form as Hadoop does not enforce them to be in a specific structure. So, we can safely store Blu-Ray™ Movies, CSV (Comma Separated Value) Files, AVRO Encoded Files, and so on inside this data layer.
You might be wondering why we are not using the word HDFS ...
