Prerequisites, Restrictions, and Recommendations for AlwaysOn Availability Groups (SQL Server)
http://msdn.microsoft.com/en-us/library/ff878487.aspx
Maximum number of availability groups and availability databases per computer: The actual number of databases and availability groups you can put on a computer (VM or physical) depends on the hardware and workload, but there is no enforced limit. Microsoft has extensively tested with 10 AGs and 100 DBs per physical machine. Signs of overloaded systems can include, but are not limited to, worker thread exhaustion, slow response times for AlwaysOn system views and DMVs, and/or stalled dispatcher system dumps. Please make sure to thoroughly test your environment with a production-like workload to ensure it can handle peak workload capacity within your application SLAs. When considering SLAs be sure to consider load under failure conditions as well as expected response times.
Best Regards,Uri Dimant SQL Server MVP, http://sqlblog.com/blogs/uri_dimant/
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