1. Quiz: HDFS

Which of the following is true?

2. Quiz: DataNode

Which of the following is true if one of the nodes running the DataNode daemon on the cluster fails?

3. Quiz: NameNode

What precautions can you take to reduce the likelihood of problems related to NameNode failure?

4. Quiz: MapReduce

If you run a MapReduce job and specify an output directory in HDFS which already exists, which of the following happens?

5. Quiz: Key

Think about the data set we used in Lesson 2. If we wanted to work out how many people had purchased goods using a particular credit card, what could we use as the key emitted by the Mappers?

6. Quiz: Block Size

Why is Hadoop’s block size set to 64MB by default, when most filesystem have block sizes of 16KB or less?