Memcached demonstrated that in-memory indexes
can be highly scalable, distributing and replicating
objects over multiple nodes.
• Dynamo pioneered the idea of eventual
consistency as a way to achieve higher availability
and scalability: data fetched are not guaranteed to
be up-to-date, but updates are guaranteed to be
propagated to all nodes eventually.
• BigTable demonstrated that persistent record
storage could be scaled to thousands of nodes, a
feat that most of the other systems aspire to