Why is the consistent hashing algorithm used and what problems does it help solve?

Consistent hashing algorithm is used for evenly distributing data across a set of nodes (such as servers or caches) and minimizing data redistribution when the number of nodes changes. This is especially important in distributed systems where nodes can be added or removed.

The main tasks solved by consistent hashing:

• Minimizing key movement: When a node is added or removed, only a small percentage of keys are redistributed, not the entire database.
• Load balancing: Keys are evenly distributed across nodes, preventing overload on individual servers.
• Scalability: Easily add or remove nodes without significant downtime or complex data migrations.

An example of application is a distributed cache (e.g., Memcached), where changing the number of servers does not require redistributing all keys, only those that are assigned to the new or removed server.