C100DBA Philosophy and Features Practice Question

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

• ✓

  Replica sets

  Why this is correct

  Replica sets provide automatic failover and data redundancy by maintaining multiple copies of data across nodes. If the primary node fails, an election automatically promotes a secondary to primary, ensuring continuous availability. This built-in mechanism aligns with MongoDB's philosophy of high availability and durability without manual intervention, making it the correct choice for the scenario.

• ✗

  Write concern

  Why it's wrong here

  Write concern defines the level of acknowledgment required for a write operation, such as waiting for a majority of replica set members to acknowledge. While it affects durability, it is not a mechanism for automatic failover or redundancy by itself. Write concern works in conjunction with replica sets, but it does not provide the automatic failover capability.

• ✗

  Journaling

  Why it's wrong here

  Journaling ensures that writes are persisted to an on-disk journal before being applied to the data files, which helps with crash recovery on a single node. However, it does not provide redundancy across multiple servers or automatic failover. Journaling is a durability feature at the storage engine level, not a high-availability solution.

• ✗

  Sharding

  Why it's wrong here

  Sharding distributes data across multiple servers to scale horizontally, but it does not provide automatic failover or redundancy. If a shard goes down, data on that shard may be unavailable unless each shard is itself a replica set. Sharding addresses scalability, not high availability, so it does not directly ensure data durability across servers.