MongoDB Questions and Answers – Sharded Cluster Data Management – 2

This set of MongoDB online quiz focuses on “Sharded Cluster Data Management – 2”.

1. _______ enables the balancer and waits for balancing to start.
a) sh.waitForBalancer()
b) sh.startBalancer()
c) sh.waitForDLock()
d) all of the mentioned
View Answer

Answer: b
Explanation: sh.waitForDLock() waits for a specified distributed sharded cluster lock.

2. Point out the correct statement.
a) sh.deadForDLock() waits for a specified distributed sharded cluster lock
b) sh.waitForBalancerOff() waits until the balancer stops running
c) sh.statusserver() reports on the status of a sharded cluster, as db.printShardingStatus()
d) all of the mentioned
View Answer

Answer: a
Explanation: sh.stopBalancer() disables the balancer and waits for any in progress balancing rounds to complete.

3. _________ waits for a change in ping state from one of the mongos in the sharded cluster.
a) sh.waitForBalancer()
b) sh.startBalancer()
c) sh.waitForPingChange()
d) all of the mentioned
View Answer

Answer: c
Explanation: sh.waitForBalancer() waits for the balancer state to change.

4. _______ forces an update to the cluster metadata cached by a mongos.
a) config
b) flushconf
c) flushRouterConfig
d) all of the mentioned
View Answer

Answer: c
Explanation: flushRouterConfig clears the current cluster information cached by a mongos instance and reloads all sharded cluster metadata from the config database.

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5. Point out the wrong statement.
a) moveChunks provides the ability to combine chunks on a single shard
b) setShardVersion is used to set the config server version
c) shardCollection enables the sharding functionality for a collection, allowing the collection to be sharded
d) none of the mentioned
View Answer

Answer: d
Explanation: For a sharded collection, mergeChunks combines contiguous chunk ranges on a shard into a single chunk.

6. Which of the following command that validates index on shard key?
a) checkShardingIndex
b) checkSIndex
c) enableSharding
d) all of the mentioned
View Answer

Answer: a
Explanation: checkShardingIndex is an internal command that supports sharding functionality.

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7. Which of the following command is used to determine split points?
a) splitVector
b) medianKey
c) movePrimary
d) none of the mentioned
View Answer

Answer: a
Explanation: movePrimary reassigns the primary shard when removing a shard from a sharded cluster.

8. You can only issue listShards against the ________ database.
a) local
b) admin
c) temp
d) none of the mentioned
View Answer

Answer: b
Explanation: listShards is only available for mongos instances.

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9. _________ is an internal command that supports the sharding functionality.
a) getBalancerHost()
b) getShardMap
c) enableSharding()
d) all of the mentioned
View Answer

Answer: b
Explanation: sh.getBalancerHost() returns the name of a mongos that’s responsible for the balancer process.

10. ________ command verifies that a process is a mongos.
a) medianKey
b) isdbgrid
c) movePrimary
d) none of the mentioned
View Answer

Answer: b
Explanation: The isdbgrid command is not available to mongod.

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Sanfoundry Global Education & Learning Series – MongoDB.

Here’s the list of Best Books in MongoDB.

To practice all areas of MongoDB for online quizzes, Here is complete set of 1000+ Multiple Choice Questions and Answers.

If you find a mistake in question / option / answer, kindly take a screenshot and email to [email protected]

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Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He lives in Bangalore, and focuses on development of Linux Kernel, SAN Technologies, Advanced C, Data Structures & Alogrithms. Stay connected with him at LinkedIn.

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