CASSANDRA MCQ 4

Question 1

A Cassandra keyspace uses replication factor 3. What is the minimum number of replicas that must respond for a QUORUM read to succeed?

Accepted Answer

2

Answer

QUORUM is calculated as floor(replication_factor / 2) + 1, so with RF=3, at least 2 replicas must respond.

Question 2

Which consistency level guarantees that a write is acknowledged only after it is persisted to all replicas, including those in remote datacenters?

Accepted Answer

ALL

Answer

ALL requires every replica across all datacenters to acknowledge the write, giving the strongest consistency but lowest availability.

Question 3

What is hinted handoff in Apache Cassandra?

Accepted Answer

A mechanism that stores missed writes for a temporarily unavailable node and delivers them when it recovers

Answer

When a replica is down during a write, the coordinator stores a 'hint' and replays it to the target node once it comes back online, reducing the need for full repair.

Question 4

Which NetworkTopologyStrategy parameter controls how many replicas are placed per datacenter?

Accepted Answer

Per-datacenter replication_factor entries in the strategy options

Answer

NetworkTopologyStrategy accepts a separate replication factor for each datacenter as named options (e.g., 'dc1': 3, 'dc2': 2).

Question 5

What does read repair do in Cassandra?

Accepted Answer

Fixes inconsistencies between replicas by synchronizing data during a read request

Answer

During a read, if the coordinator detects replica disagreement, it initiates a background (or foreground) repair to bring all replicas to the latest version.

CASSANDRA - Apache Cassandra Database Practice Test

CASSANDRA - Apache Cassandra Database Practice Test

CASSANDRA MCQ 4