Category: Big Data Technology

The HDFS client software implements __________ checking on the contents of HDFS files.

administrator
The HDFS client software implements __________ checking on the contents of HDFS files.
checksum
Excellent ! Your Answer is Correct. Explanation: When a client creates an HDFS file, it computes a checksum of each block of the file and stores these checksums in a separate hidden file in the same HDFS namespace.
metastore
parity
None of the Option is Correct

__________ is a generalization of the facility provided by the MapReduce framework to collect data output by the Mapper or the Reducer.

administrator
__________ is a generalization of the facility provided by the MapReduce framework to collect data output by the Mapper or the Reducer.
OutputCollector
Excellent ! Your Answer is Correct. Explanation: Hadoop MapReduce comes bundled with a library of generally useful mappers, reducers, and partitioners.
Partitioner
Reporter
All Options are Correct

Mapper and Reducer implementations can use the ________ to report progress or just indicate that they are alive.

administrator
Mapper and Reducer implementations can use the ________ to report progress or just indicate that they are alive.
Reporter
Excellent ! Your Answer is Correct. Explanation: Reporter is a facility for MapReduce applications to report progress, set application-level status messages and update Counters.
Partitioner
OutputCollector
All Options are Correct

Point out the wrong statement.

administrator
Point out the wrong statement.
Reducer has 2 primary phases
Excellent ! Your Answer is Correct.
Increasing the number of reduces increases the framework overhead, but increases load balancing and lowers the cost of failures
It is legal to set the number of reduce-tasks to zero if no reduction is desired
The framework groups Reducer inputs by keys (since different mappers may have output the same key) in the sort stage

Point out the correct statement.

administrator
Point out the correct statement.
All Options are Correct
Excellent ! Your Answer is Correct. Explanation: Reporters can be used to set application-level status messages and update Counters.
Applications can use the Reporter to report progress
The Hadoop MapReduce framework spawns one map task for each InputSplit generated by the InputFormat for the job
The intermediate, sorted outputs are always stored in a simple (key-len, key, value-len, value) format

Hadoop achieves reliability by replicating the data across multiple hosts, and hence does not require ________ storage on hosts.

administrator
Hadoop achieves reliability by replicating the data across multiple hosts, and hence does not require ________ storage on hosts.
RAID
Excellent ! Your Answer is Correct. With the default replication value, 3, data is stored on three nodes: two on the same rack, and one on a different rack.
Standard RAID levels
ZFS
Operating system
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