MCQs on Replication and High Availability | MongoDB MCQs
Replication is a vital feature in MongoDB for ensuring high availability and data redundancy. By leveraging replica sets, automatic failover, and flexible read and write configurations, MongoDB ensures robust performance under various scenarios. Test your understanding with these thoughtfully crafted multiple-choice questions (MCQs) covering all key aspects of replication.
Multiple-Choice Questions (MCQs)
1. Understanding Replica Sets
- What is a MongoDB replica set?
a) A group of collections with the same schema
b) A set of databases in different servers
c) A group of MongoDB instances with data replication
d) A backup of MongoDB collections - How many nodes are recommended in a production replica set for fault tolerance?
a) 1
b) 2
c) 3
d) 5 - The primary node in a replica set:
a) Serves as a backup only
b) Handles all read and write operations
c) Synchronizes data from the secondary node
d) Is optional for the replica set - A secondary node in a replica set:
a) Accepts write operations directly
b) Stores only indexes
c) Copies data from the primary node
d) Controls election processes - What is an arbiter node in MongoDB?
a) A node that stores data
b) A node that participates in elections but does not store data
c) A node used for backups
d) A node dedicated to analytics - Which command is used to initiate a replica set in MongoDB?
a)rs.initialize()
b)rs.init()
c)rs.start()
d)rs.initiate()
2. Automatic Failover and Elections
- What happens during a replica set election?
a) A new primary is selected
b) The replica set shuts down temporarily
c) Data is deleted on secondary nodes
d) Indexes are rebuilt on all nodes - What is the default priority for election of a primary node?
a) 1
b) 0
c) -1
d) 5 - How does an arbiter node help in a replica set?
a) By storing backups of primary data
b) By participating in elections to maintain quorum
c) By balancing the read/write load
d) By optimizing query performance - What happens if the primary node in a replica set fails?
a) All operations stop until the primary is restored
b) A secondary node is automatically promoted to primary
c) The replica set goes into read-only mode
d) An arbiter node takes over primary responsibilities - Which parameter defines the time interval for MongoDB’s replica set heartbeat checks?
a)electionTimeoutMillis
b)heartbeatFrequencyMS
c)replicaTimeout
d)primaryCheckInterval - Failover time in MongoDB replica sets depends on:
a) Data size
b) Number of nodes
c) Election timeout settings
d) Network latency
3. Read Preferences and Write Concerns
- The default read preference in a MongoDB replica set is:
a)secondary
b)nearest
c)primary
d)any - Which read preference routes queries to the nearest node?
a)primaryPreferred
b)secondary
c)nearest
d)secondaryPreferred - What does
writeConcern: {w: "majority"}mean?
a) Write operations will wait for all nodes to acknowledge
b) Write operations will wait for the majority of nodes to acknowledge
c) Write operations occur only on the primary node
d) Writes are performed asynchronously - The
j: trueoption in write concern ensures:
a) Faster writes
b) Writes are acknowledged after being written to the journal
c) Writes are performed on secondary nodes first
d) Writes are distributed among all nodes - Which read preference minimizes data latency but may lead to stale reads?
a)primary
b)nearest
c)secondary
d)primaryPreferred - What is the purpose of
wtimeoutin write concerns?
a) Limit the query execution time
b) Set a time limit for write acknowledgment
c) Control the number of nodes for write operations
d) Define timeouts for read preferences
4. Replication Use Cases
- Which of the following is a primary advantage of replication?
a) Faster backups
b) High availability
c) Reduced storage requirements
d) Improved schema design - In a geographically distributed replica set, the best read preference is:
a)primaryPreferred
b)nearest
c)secondaryPreferred
d)primary - Replication can be used for:
a) Improving indexing performance
b) Scaling writes across multiple nodes
c) Disaster recovery and failover
d) Schema migrations - MongoDB replication is not suitable for:
a) Fault tolerance
b) Data archival
c) Load balancing writes
d) Disaster recovery - A use case where MongoDB’s
secondaryread preference is ideal:
a) Real-time analytics
b) Reporting and background queries
c) High-frequency writes
d) Transactional workloads - Which replication use case benefits from
writeConcern: {w: 1}?
a) Critical systems requiring durability
b) High-performance applications tolerating potential data loss
c) Long-running analytics queries
d) Distributed event processing - What is a major drawback of replication in MongoDB?
a) Increased latency
b) Additional storage overhead
c) Lack of read scalability
d) Complexity in query design
Answer Key
| Qno | Answer (Option with Text) |
|---|---|
| 1 | c) A group of MongoDB instances with data replication |
| 2 | c) 3 |
| 3 | b) Handles all read and write operations |
| 4 | c) Copies data from the primary node |
| 5 | b) A node that participates in elections but does not store data |
| 6 | d) rs.initiate() |
| 7 | a) A new primary is selected |
| 8 | a) 1 |
| 9 | b) By participating in elections to maintain quorum |
| 10 | b) A secondary node is automatically promoted to primary |
| 11 | b) heartbeatFrequencyMS |
| 12 | c) Election timeout settings |
| 13 | c) primary |
| 14 | c) nearest |
| 15 | b) Write operations will wait for the majority of nodes to acknowledge |
| 16 | b) Writes are acknowledged after being written to the journal |
| 17 | b) nearest |
| 18 | b) Set a time limit for write acknowledgment |
| 19 | b) High availability |
| 20 | b) nearest |
| 21 | c) Disaster recovery and failover |
| 22 | c) Load balancing writes |
| 23 | b) Reporting and background queries |
| 24 | b) High-performance applications tolerating potential data loss |
| 25 | b) Additional storage overhead |
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