Cloudera
CCA-500 · Question #28
On a cluster running MapReduce v2 (MRv2) on YARN, a MapReduce job is given a directory of 10 plain text files as its input directory. Each file is made up of 3 HDFS blocks. How many Mappers will run?
The correct answer is C. 30. Each block will have a Mapper running, 3 blocks for a file, 3*10 = 30 Mappers
Resource Management
Question
On a cluster running MapReduce v2 (MRv2) on YARN, a MapReduce job is given a directory of 10 plain text files as its input directory. Each file is made up of 3 HDFS blocks. How many Mappers will run?
Options
- AWe cannot say; the number of Mappers is determined by the ResourceManager
- BWe cannot say; the number of Mappers is determined by the developer
- C30
- D3
- E10
- FWe cannot say; the number of mappers is determined by the ApplicationMaster
How the community answered
(31 responses)- A6% (2)
- B3% (1)
- C71% (22)
- D16% (5)
- E3% (1)
Explanation
Each block will have a Mapper running, 3 blocks for a file, 3*10 = 30 Mappers
Topics
#Mapper count#input splits#HDFS blocks#MapReduce input
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