One thing completely puzzles me about how hadoop is positioned, on the one hand there is this accent on reliability and scalability, then on the other there is the single meta data node.
How does that work in practice, surely there must be some way to have multiple meta-data stores ?
It includes Hive pre-installed and Pig as well. It also has a list of tutorial exercises an sample databases for you to practice on.
I'm not really a Hadoop expert to be able to address the data store issue. I'm basically one of two researchers at our company that is testing out these new technologies for select tasks (parsing log data, machine learning algorithm implementations, quick statistical munging, etc). In our configuration we have 7 nodes and roughly 3 TB capacity (although we're scaling as our needs increase). For our needs it works quite well. There was an instance where one of our nodes went down while in the middle of a big processing job, and Hadoop kept chugging. Quite amazing.