Design a distributed cache system (like Memcached/Redis Cluster).

Consistent hashing: distribute keys across cache nodes; minimize reshuffling on node change Virtual nodes: 150 vnodes per physical node for even distribution Replication: each key replicated to N nodes for fault tolerance Eviction: LRU per shard; configurable maxmemory policy Failure handling: if node fails, client routes to next node on ring (degraded mode) Connection pooling: each client maintai