Design a Distributed Cache

Build a distributed caching system similar to Redis or Memcached that provides high-speed key-value storage across multiple nodes.

Functional Requirements

• Store and retrieve key-value pairs with sub-millisecond latency
• Support TTL (time-to-live) for automatic expiration
• Handle multiple data types (strings, lists, sets, hashes)
• Support atomic operations (increment, compare-and-swap)
• Provide pub/sub messaging capabilities

Non-Functional Requirements

• Horizontal scalability to petabytes of data
• 99.99% availability
• Consistent performance under high load
• Support for 1M+ operations per second per node

Questions to Consider

• How will you partition data across nodes?
• What consistency model will you use?
• How do you handle node failures and rebalancing?