Engineering Questions with Answers - Multiple Choice Questions
MCQs on MapReduce Job – 1
1 - Question
__________ storage is a solution to decouple growing storage capacity from compute capacity.
a) DataNode
b) Archival
c) Policy
d) None of the mentioned
View Answer
Answer: b
Explanation: Nodes with higher density and less expensive storage with low compute power are becoming available.
2 - Question
Point out the correct statement.
a) When there is enough space, block replicas are stored according to the storage type list
b) One_SSD is used for storing all replicas in SSD
c) Hot policy is useful only for single replica blocks
d) All of the mentioned
View Answer
Answer: a
Explanation: The first phase of Heterogeneous Storage changed datanode storage model from a single storage.
3 - Question
___________ is added for supporting writing single replica files in memory.
a) ROM_DISK
b) ARCHIVE
c) RAM_DISK
d) All of the mentioned
View Answer
Answer: c
Explanation: DISK is the default storage type.
4 - Question
Which of the following has high storage density?
a) ROM_DISK
b) ARCHIVE
c) RAM_DISK
d) All of the mentioned
View Answer
Answer: b
Explanation: Little compute power is added for supporting archival storage.
5 - Question
Point out the wrong statement.
a) A Storage policy consists of the Policy ID
b) The storage policy can be specified using the “dfsadmin -setStoragePolicy” command
c) dfs.storage.policy.enabled is used for enabling/disabling the storage policy feature
d) None of the mentioned
View Answer
Answer: d
Explanation: The effective storage policy can be retrieved by the “dfsadmin -getStoragePolicy” command.
6 - Question
Which of the following storage policy is used for both storage and compute?
a) Hot
b) Cold
c) Warm
d) All_SSD
View Answer
Answer: a
Explanation: When a block is hot, all replicas are stored in DISK.
7 - Question
Which of the following is only for storage with limited compute?
a) Hot
b) Cold
c) Warm
d) All_SSD
View Answer
Answer: b
Explanation: When a block is cold, all replicas are stored in the ARCHIVE.
8 - Question
When a block is warm, some of its replicas are stored in DISK and the remaining replicas are stored in _________
a) ROM_DISK
b) ARCHIVE
c) RAM_DISK
d) All of the mentioned
View Answer
Answer: b
Explanation: Warm storage policy is partially hot and partially cold.
9 - Question
____________ is used for storing one of the replicas in SSD.
a) Hot
b) Lazy_Persist
c) One_SSD
d) All_SSD
View Answer
Answer: c
Explanation: The remaining replicas are stored in DISK.
10 - Question
___________ is used for writing blocks with single replica in memory.
a) Hot
b) Lazy_Persist
c) One_SSD
d) All_SSD
View Answer
Answer: b
Explanation: The replica is first written in RAM_DISK and then it is lazily persisted in DISK.