[Intro to Hadoop and MapReduce] Lesson 4 Problem set
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?