Consistent hashing
Before you understand its implication and application in Cassandra, let's understand consistent hashing as a concept.
Consistent hashing works on the concept in its name—that is hashing and as we know, for a said hashing algorithm, the same key will always return the same hash code—thus, making the approach pretty deterministic by nature and implementation. When we use this approach for sharding or dividing the keys across the nodes in the cluster, consistent hashing is the technique that determines which node is stored in which node in the cluster.
Have a look at the following diagram to understand the concept of consistent hashing; imagine that the ring depicted in the following diagram represents the Cassandra ring and the nodes are marked here in letters along with the numerals that actually mark the objects (inverted triangles) to be mapped to the ring.
Consistent hashing for the Cassandra cluster
To compute the ownership of the object to the node it belongs to, all...
