Hadoop Quiz / Hadoop MCQ Set 7

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3:36:24 PM

Hadoop MCQ  Set 7

1. The Hadoop tool used for uniformly spreading the data across the data nodes is named
Scheduler
Balancer
Spreader
Reporter


2. Running Start-dfs.sh results in
 Starting namenode and resource manager
Starting datanode only
Starting namenode only
Running Start-dfs.sh results in


3. All the files in a directory in HDFS can be merged together using
 getmerge
putmerge
mergeall
remerge


4. Which of the following is not a scheduling option available in YARN
 Fair scheduler
Capacity scheduler
Balanced scheduler
FiFO schesduler.


5. FiFO schesduler.
 Yes, but additional extensive coding is required.
Yes, Avro was specifically designed for data processing via Map-Reduce.
Avro specifies metadata that allows easier data access. This data cannot be used as part of map-reduce execution, rather input specification only.
No, Avro was specifically designed for data storage only.


6. When writing data to HDFS what is true if the replication factor is three? (Choose 2 answers) 1. Data is written to DataNodes on three separate racks (if Rack Aware). 2. The Data is stored on each DataNode with a separate file which contains a checksum value. 3. Data is written to blocks on three different DataNodes. 4. The Client is returned with a success upon the successful writing of the first block and checksum check.
1 & 3
2 & 3
4 & 3
1 & 2


7. In a Hadoop cluster, what is true for a HDFS block that is no longer available due to disk corruption or machine failure?
 It is lost for ever
The Mapreduce job process runs ignoring the block and the data stored in it.
The namenode allows new client request to keep trying to read it.
It can be replicated form its alternative locations to other live machines.


8. What mechanisms Hadoop uses to make namenode resilient to failure.
 Using expensive and reliable hardware.
Use a machine with at least 12 CPUsUse a machine with at least 12 CPUs
Store the filesystem metadata in cloud.
Take backup of filesystem metadata to a local disk and a remote NFS mount.


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