Enhancing scalability and data replication

In this section, we will explore how consistent hashing can bolster scalability and how to replicate partitioned data efficiently.

Boosting scalability

One of the essential design requirements for our system is scalability. We store key-value data across multiple storage nodes. Depending on demand, we might need to augment or diminish these storage nodes. This implies that we must distribute data across all nodes in the system to evenly distribute the load.

For instance, consider a scenario where we have four nodes, and we aim to balance the load equally by directing 25% of requests to each node. Traditionally, we would use the modulus operator to achieve this. Each incoming request comes with an associated key. On receiving a request, we calculate the hash of the key and then find the remainder when the hashed value is divided by the number of nodes (m). The remainder value (x) indicates the node number to which we route the request...