Cassandra Practice Test

What does a replication factor greater than one cause in a Cassandra cluster?

1. Widening the range of token values

2. Causes overlap in the token ranges amongst nodes

3. Requires more storage in your cluster

4. All of the above

The correct answer is: All of the above

A replication factor greater than one in a Cassandra cluster leads to a variety of outcomes that are essential for understanding data distribution and availability across the nodes. When the replication factor is increased, the system needs to manage multiple copies of each piece of data. This naturally results in requiring more storage because, with more replicas of each piece of data distributed across the cluster, the total amount of disk space used increases. Consequently, each node will store a copy of the data based on the replication factor, accumulating additional storage needs. Additionally, having a replication factor greater than one causes overlap in the token ranges among the nodes because nodes will be responsible for multiple replicas of data. In Cassandra, data is distributed across nodes using consistent hashing based on token values. When a replication factor is greater than one, multiple nodes will take on the responsibility of storing the same token range to ensure that there are redundant copies of the data for fault tolerance and high availability. This leads to an overlap in token ranges that can affect how data is managed across the cluster. Lastly, with a higher replication factor, the range of token values that contribute to the distribution of data is effectively widened because more nodes contribute to storing each piece of data, thereby increasing the complexity and potential range of token values utilized