I've been necessarily brief explaining both Memcached and LiveJournal's backend, so please e-mail me at brad@danga.com for any more information. Also, check out the Memcached site (www.danga.com/memcached) and the Memcached mailing list.
Bonwick, Jeff. “The Slab Allocator: An Object-Caching Kernel Memory Allocator.” Boston USENIX Proceedings, 1994 (www.usenix.org/publications/library/proceedings/bos94/bonwick.html).
libevent: monkey.org/~provos/libevent
