Consistent Hashing

Consistent Hashing is a smart way to distribute data across multiple servers so that minimum disruption happens when a server is added or removed.

🎯 Simple Explanation:

Imagine you have 100 lockers and you’re storing books based on the book’s name.
If you suddenly remove a few lockers (servers), all books get shuffled — that’s bad.

Consistent hashing solves this by putting lockers in a circle (hash ring).
Now, when a book is added, it goes to the locker clockwise from its hash.

🌀 If a locker (server) is removed or added:

• Only a few books need to move
• Most of the books stay where they are

💡 Why it’s useful:

• Used in distributed systems like caching (e.g., Redis, Memcached), databases
• Keeps systems scalable and stable under dynamic changes

📦 Real-Life Analogy:

Think of people standing in a circle passing out cards. If one person leaves, only the person before them changes who they hand cards to — not everyone.