Seconded, please explain. I don't have a view but was wondering about using Berkeley DB, including its replication, to have the web server running on each machine, with the BDB library linked in. Each machine would be a web server but also one of the replication group, with one master and many replicas. Writes go to the master, reads can be shared around the replicas.

BDB seems pretty flexible in policy decisions, e.g. the master can say the commit is complete when it hears back from N replicas depite not having written to disc itself yet.