Replication in MongoDB

What is the main factor for NoSQL databases?

• Transactions

• Clusters

• Indexes

• Joins

Answer explanation

The main factor for NoSQL databases is clusters, which allow for horizontal scaling and high availability of data across multiple servers.

Which option is NOT a method for scaling in NoSQL databases?

• Scaling out (horizontal)

• Scaling down (diagonal)

• Scaling in (concentric)

• Scaling up (vertical)

Answer explanation

Scaling down (diagonal) is NOT a method for scaling in NoSQL databases. The correct methods are scaling out (horizontal), scaling in (concentric), and scaling up (vertical).

What is a node in the context of distributed databases?

• A type of data structure

• A type of query language

• A computer that offers processing, local storage, and is connected to other nodes

• A type of network protocol

Answer explanation

A node in the context of distributed databases refers to a computer that offers processing, local storage, and is connected to other nodes, enabling distributed data processing and storage.

What does replication do in databases?

• Encrypts data on servers

• Deletes data from servers

• Copies the same data across multiple servers

• Moves data between servers

Answer explanation

Replication in databases involves copying the same data across multiple servers to ensure redundancy and improve availability and performance.

Which type of consistency guarantees that a read will get the most up-to-date data?

• Weak consistency

• Strong consistency

• Eventual consistency

• Strict consistency

Answer explanation

Strict consistency guarantees that a read will get the most up-to-date data, making it the correct choice in this scenario.

What is the purpose of automatic failover in a replica set?

• To replace a primary node with a secondary node automatically

• To increase the number of nodes in the cluster

• To synchronize data between nodes

• To perform backups of the data

Answer explanation

Automatic failover in a replica set is used to replace a primary node with a secondary node automatically, ensuring high availability and fault tolerance.

In MongoDB, what is the primary node responsible for?

• Acting as a backup node

• Storing only read operations

• Receiving all write operations from clients

• Performing maintenance tasks

Answer explanation

The primary node in MongoDB is responsible for receiving all write operations from clients.

What is the benefit of using eventual consistency in some applications?

• Reduced data distance travel

• Increased data redundancy

• Guaranteed up-to-date data on all reads

• Improved performance by spreading reads across multiple secondary nodes

Answer explanation

The benefit of using eventual consistency in some applications is improved performance by spreading reads across multiple secondary nodes.

Which type of replication is used in MongoDB?

• Synchronous

• Asynchronous

• Simultaneous

• Sequential

Answer explanation

MongoDB uses Asynchronous replication where data is replicated to secondary nodes without waiting for confirmation from the primary node.

What is the purpose of sharding in NoSQL databases?

• Distributes different data across multiple servers

• Encrypts data on servers

• Combines data into a single server

• Deletes data from servers

Answer explanation

Sharding in NoSQL databases distributes different data across multiple servers to improve scalability and performance.