Largest Redis Cluster Ever
xdata.me
xdata.me
EDIT: btw, the reason why I don't know much about this use cases is that the hardcore hackers at Twitter and Weibo simply never ask for help. They know Redis internals perfectly so can fix their stuff, tune everything and so forth. That's quite cool.
I'm hoping that once the Redis Cluster project is production ready it will make it easier and more feasible for anyone to run a large Redis cluster.
For rails: redis-rails # unmaintained in 3-5 months :(, but plenty of forks and contrib :)
For node: connect-redis
For django: django-redis-cache
I've been using this one for some time now, however I haven't stress-tested it in a production environment:
https://github.com/vmihailenco/redis
As for PHP I've had issues with predis'[1] performance, whereas phpredis[2] has been nothing short of fantastic.