A new white paper is available from http://www.mysql.com/why-mysql/white-papers/mysql_wp_cluster_ScalingWebServices.php
MySQL and memcached has become, and will remain, the foundation for many dynamic web services with proven deployments in some of the largest and most prolific names on the web.
There are classes of web services however that are highly transactional and update-intensive, demanding real-time responsiveness and continuous availability. In these cases, MySQL Cluster provides the familiarity and ease-of-use of the regular MySQL Server, while delivering significantly higher levels of write performance with less complexity, lower latency and 99.999% availability.
This whitepaper will discuss the use-cases for both approaches, and provides an insight into how MySQL Cluster is enabling users to scale update-intensive web services.