Redis and Memcached at scale.
Distributed Caches: redis and memcached at scale
absorb bursts before they become outages
Multi-key ops constrained to a slot.
Distributed caches add capacity by sharding keys across nodes. Redis Cluster ships with consistent-hashing slots and replication; Memcached is simpler but lacks persistence and replication.
Redis Cluster: 16384 hash slots; clients route by slot.
Replication for failover; persistence (RDB, AOF) for restart.
Memcached scales by adding nodes; clients consistent-hash.
Move single Redis to a cluster.