Describe the HDFS Safe mode.

Describe how Hive is used in the Hadoop ecosystem.

Describe the Star Schema.

How does schema evolution work?

What do you know about FSCK?

What does Hadoop’s Heartbeat mean?

What are the differences between an operational database and a data warehouse?

What role does Apache Hadoop’s distributed cache play?

List the elements of the Hive data model.

Which two messages does NameNode get from DataNode?