Here are some best resource to learn and understand Hadoop.
Tutorials
Free videos - MapR Academia
Udacity course
Hortonworks Sandbox
Hadoop Ecosystem
Running Hadoop Map-Reduce
Hadoop Screencasts
Reza Shiftehfar's blog I
Reza Shiftehfar's blog II
Reza Shiftehfar's blog III
Reza Shiftehfar's blog IV
Reza Shiftehfar's blog V
Reza Shiftehfar's blog VI
Reza Shiftehfar's blog ...
15 May 2014
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