Redis is amazing. But I don't see much discussion about its pubsub capabilities. Are there any real-world stories of how well it scales, and how much pubsub traffic a single server can handle?
2.6 significantly improve Pub/Sub real-world reliability by implementing detection for slow readers, and closing the connection when a given (configurable) amount of memory is used by this slow consumer.
Most redis-based queues/websocket servers makes use of Redis Pub/Sub. StackOverflow uses Redis Pub/Sub for maintaining synchronized local caches in their load balanced web servers. Whilst StackOverflow Careers uses a Pub/Sub powered RedisMQ host for its BackOffice services: https://github.com/ServiceStack/ServiceStack/wiki/Messaging-...
NewsBlur (social feed reader) uses Redis pubsub for real-time as well: http://blog.newsblur.com/post/20371256202/building-real-time.... Now I'll have up to 500 concurrent clients, but I couldn't be happier with how utterly simple it was to get Python to talk to Redis to talk to Node to talk to Socket.IO in JavaScript on the browser.
I use it during feed fetching to notify all of the users subscribed to a feed's updates.
