Is there support for a cluster of iis nodes when using SignalR? Or do I need some third party message bus?
Not yet, but they are working on it.
It's planned for the 0.4 release.
When ready, more information will probably be published in the wiki: SignalR and Webfarms on the wiki
Edit2:
Azure, SQL-Server and Redis are implemented.
We just implemented this addon in our application and so far it works flawlessly. It uses a RabbitMq instance to distribute the messages to other servers and is really easy to configure.
https://github.com/mdevilliers/SignalR.RabbitMq
We haven't tried this on a production server yet.
来源：https://stackoverflow.com/questions/8976595/how-to-implement-signalr-if-there-is-more-than-one-iis-server