Memcached Memory Cache

Memcached is a free and open source high performance distributed memory object caching system, originally created by Brad Fitzpatrick in 2003 for the LiveJournal blogging platform and now used by some of the largest websites in the world including YouTube, Reddit, Twitter, Facebook, Wikipedia, and Craigslist. The system is generic in nature but intended for use in speeding up dynamic web applications by alleviating database load. It operates as an in memory key value store for small chunks of arbitrary data such as strings, objects, or serialized structures, with a simple text and binary protocol that clients use to store and retrieve data. The architecture is intentionally simple: servers maintain a slab allocator with fixed size memory chunks organized into slab classes, and items are stored in the smallest slab class that fits. Eviction follows a least recently used policy within each slab class, and expired items are lazily removed on access. The maximum object size is 1 megabyte by default, and the system is designed for high throughput with O of 1 operations for both reads and writes. Clients implement consistent hashing to distribute keys across multiple server nodes, providing horizontal scalability and fault tolerance through redundancy. Memcached operates as a daemon on port 11211 and communicates over TCP or UDP. The BSD licensed project has accumulated over 13,000 GitHub stars and remains the reference implementation for distributed caching.