From the dev blog A Failure to Launch:
Our Redis server keeps causing bugs and continues to be a thorn in our side. We increased the Output Buffer through Redis Config to try to deal with the no-response issues, but this caused an even greater error. Though the Redis server now responded, we now had issues with the free Heap Memory having an Recv bug. But not only is the free Heap Memory having Recv issues, but the other memory is also plagued with Recv, causing the server to die. It looks more and more like a Tuesday launch will not be possible…When I look back at it now, I feel we didn’t make enough time for server testing, and I really regret it. We set this launch schedule because of our rapidly dwindling finances… trying to make a game without funding is hard, hard work.
If anyone has any experience with Redis, we'd love the help!