Explain the principle of consistent hashing and its advantages in distributed systems.

Consistent hashing is an algorithm for distributing data across nodes in a distributed system in such a way as to minimize data redistribution when nodes are added or removed.

Working principle:

• All nodes and keys are mapped onto a hash ring (e.g., 0..2^32-1).
• Each key is stored on the first node clockwise after the key's position on the ring.
• When a node is added or removed, only the keys that fall within the range between the new node and its neighbor are redistributed, not all keys.

Advantages:

• High resilience to cluster changes — minimal data movement.
• Good load balancing among nodes.
• Simplifies scaling and maintenance of the system.

Example of use: cache systems (e.g., Memcached) use consistent hashing for evenly distributing keys across servers and minimizing losses when server composition changes.