How many replicas can I have in an Alwayson availability group?
Each availability group supports one primary replica and up to eight secondary replicas. For more information, see Overview of Always On Availability Groups (SQL Server). Each availability replica must reside on a different node of a single Windows Server Failover Clustering (WSFC) cluster.
How many databases can SQL support on a single server?
32,767
For SQL Server, the max number of databases you can have on a single SQL Server instance is 32,767.
Can a cluster node participate in multiple Availability groups?
The cluster node can participate in multiple availability groups, with one replica from each group. Ask your database administrators how many cluster nodes are required for to support the availability replicas of the planned availability groups.
Do you have to be a WSFC node to host an availability group?
The host computer must be a WSFC node. The instances of SQL Server that host availability replicas for a given availability group reside on separate nodes of the cluster. An availability group can temporarily straddle two clusters while being migrated to different cluster. SQL Server 2016 introduces distributed availability groups.
Do you need shared storage for always on availability groups?
Always On availability groups does not depend on any form of shared storage. However, if you use a SQL Server failover cluster instance (FCI) to host one or more availability replicas, each of those FCIs will require shared storage as per standard SQL Server failover cluster instance installation.
Where does the availability group reside in SQL Server?
In a distributed availability group two availability groups reside on different clusters. All server instances that host an availability replica for the availability group must use the same SQL Server service account.