Big Data Online Practice Test - 15

Q. A group of developers, were given some statements,regarding speculative execution,in Hadoop. Mark the Valid (V) or Invalid(In) ones.
1) In Hadoop, the speculative execution is disabled by default.
2) This feature,if running, can reduce the overall throughput.
3) This feature ,if running,improves job efficiency.
4) If the original task completes,before the speculative task, then, the later one is discarded.
Mark the correct option.

Q. Match the following technologies, and their proper usefulness,in the Hadoop ecosystem.
1) Avro
2) Thrift
3) Drill
4) Mahout
a) Schema free,query engine,for big data.
b) Provides data serialization and data exchange services.
c) Creating scalable machine learning algorithm.
d) Interface definition language,for remote procedure call communication.
Mark the correct option

Q. A group of developers were debating about Namenode High Availability(HA).Consider the following statements.
Dev 1- The Hadoop 2.0 architecture allows Namenode High Availability, with the option of running two Namenodes. One active and other passive.While the active one,handles,all the clients,the passive one,is a standby slave, but,shares similar data as the active Namenode. "Fencing" allows sharing of data,between the two Namenodes.
Dev 2- The two Namenodes cannot share the same metadata. Otherwise this leads to data corruption,and,a "split-brain"scenario .After failure, the standby node,updates itself,from the journal nodes(in journal nodes implementation of HA),which have information,about the metadata."Fencing" allows,only one of the Namenode to be active.
Dev 3- The two Namenodes can share,the same metadata.But,only one of them,can be active at a time,otherwise,the "split-brain" scenario occurs.The standby Passive Namenode,updates itself, from the journal nodes(in journal nodes implementation of HA), parallely, as and when,the Active Namenode edits it.
Which of the following is correct?

Q. Consider the following value settings,and,match them with the Hadoop configuration files.
a) Mention default block replication.
b) Contains settings for Resource Manager, Node Manager,Containers etc.
c) Specify framework name for MapReduce.
d) Mentions Hadoop daemon where the NameNode runs in the cluster.
File Names
1) yarn-site.xml
2) mapred-site.xml
3) hdfs-site.xml
4) core-site.xml
Mark the correct option.

Q. Help a Hadoop fresher,write syntax for,the following problem statements,which his lead has assigned.
1) Set the number of tasks to run per jvm 2) Set maximum number of parallel map tasks,per job. 3) Set if the job outputs be compressed. Mark the correct option.

Q. In an interview,freshers were asked to mark the true or false statements,from the following.
1) The number of map tasks,is equal to,the number of Input splits.
2) Input split,does not contain actual data,but, the reference of the data.
3) InputFormat is accountable,for the creation of InputSplit.
Choose the correct answer.

Q. A developer was presented,the following scenarios,and was asked to mark the NoSql database(Mongodb(M) or Cassandra(C)), that would fit properly, in the same.
1) Use this data store,if application needs secondary indexes,and flexibility,in them.
2) Datastore that gives hundred percent uptime.
3) Not suitable for read requests.
4) Can handle massive amounts of data.
Mark the correct answer.

Q. In an interview ,freshers were given the following scenarios. Mark where Static(S) and Dynamic (D) Hive partitions,are applicable.
1) This one,takes, more time in loading data.
2) Can alter the partition,here.
3) When there is large data in a table,this is suitable.
4) This partition is in the non-strict mode.
Options present are :

Q. A developer was told to write a query as follows:
Find the documents from the Footwear collection, where Brands ends with 'r'.
Mark the correct syntax from the options provided below.

Q. A developer was brushing his knowledge,of Hadoop commands. Correctly map the problem statements,with their syntax.
a) Remove the entire 'dessert' directory and its contents.
b) Create a 0 byte size file,at path /new_emp/joindate,containing the current time as timestamp.
Mark the correct syntax.