Question 19: Which of the following components of Cassandra help you to determine which data centers and racks nodes belong to.
- Network topology
- Replication Strategy
- Snitch
- Partitioner
Correct Answer: 3
Explanation: A snitch defines groups of machines into data centers and racks (the topology) that the replication strategy uses to place replicas.
A snitch determines which data centers and racks nodes belong to. They inform Cassandra about the network topology so that requests are routed efficiently and allows Cassandra to distribute replicas by grouping machines into data centers and racks. Specifically, the replication strategy places the replicas based on the information provided by the new snitch. All nodes must return to the same rack and data center. Cassandra does its best not to have more than one replica on the same rack (which is not necessarily a physical location).
