I refer you to Dormando's oft-cited explanation of how to store sessions in MySQL with memcached caching . The original LiveJournal post is more wordy but more thoroughly explains why storing sessions in memcached only is a bad idea.
Sessions it's a temporary thing, there is nothing to worry about if once per month memcache-server will fail and truncate sessions. I'm sure you can use just memcache for sessions, without replication in DB.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.