C100DBA Sharding Practice Question
Which THREE components are mandatory architectural parts of every fully functioning MongoDB sharded cluster deployment? Choose 3 answers.
⚠ Common exam trap
Candidates often overlook the config server replica set as a mandatory component, assuming a sharded cluster only requires mongos routers and shard nodes.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
A config server replica set that stores all cluster metadata, chunk ranges, and routing configuration data.
A sharded cluster relies on three core functional components: config servers to maintain cluster metadata, mongos query routers to direct client requests, and shard replicas to store partitioned data safely. Knowing these architecture requirements helps administrators design resilient, highly available production clusters with proper redundancy at every layer of the infrastructure.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
A config server replica set that stores all cluster metadata, chunk ranges, and routing configuration data.
Why this is correct
A config server replica set that stores all cluster metadata, chunk ranges, and routing configuration data. The config server tier is mandatory because it maintains the authoritative source of truth regarding database metadata, security settings, and precise chunk range mappings across the entire cluster.
- ✓
One or more mongos query router instances that interface between client applications and the sharded cluster.
Why this is correct
One or more mongos query router instances that interface between client applications and the sharded cluster. Client applications do not connect directly to individual shards for sharded collections; instead, they issue queries through mongos routers which determine where data resides.
- ✓
Multiple shard replica sets that independently store partitions of the application dataset.
Why this is correct
Multiple shard replica sets that independently store partitions of the application dataset. Shards hold the actual user data, and implementing them as replica sets ensures high availability and automatic failover for every partitioned data segment within the cluster.
- ✗
A dedicated primary balancer coordinator node running outside the config server replica set to manage migrations.
Why it's wrong here
A dedicated primary balancer coordinator node running outside the config server replica set to manage migrations. The balancing process is coordinated internally by the primary member of the config server replica set, eliminating the need for an external standalone balancer daemon.
- ✗
An independent Apache ZooKeeper quorum cluster to coordinate distributed locking across all participating mongod nodes.
Why it's wrong here
An independent Apache ZooKeeper quorum cluster to coordinate distributed locking across all participating mongod nodes. MongoDB uses its internal config servers and replica set consensus mechanisms rather than external orchestration tools like ZooKeeper for cluster coordination.
About these practice questions
This C100DBA question is part of Courseiva's 222-question bank — original exam-style content with full explanations and wrong-answer analysis, never real exam questions or exam dumps. Learn why practice questions differ from exam dumps →
JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official MongoDB exam blueprint
This C100DBA practice question is part of Courseiva's free MongoDB certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the C100DBA exam.