SQL Server terminology question: WSFC, FCI and AG terms.
I'm having some problems wrapping my head around the SQL Server AlwaysOn terminology and what Failover Cluster Instances (FCI) and AvailabilityGroup (AG) setups actually mean.
First, is it still possible in SQL Server 2012 and up to have just the reliable Windows Server failover Cluster (WSFC) with a happy little quorum disk and cluster manager to control which node is running the database resources?
For FCI does it have the same AlwaysOn cluster manager as the AG does? I have seen some problems with legacy applications that have a set connection string interacting with the AG cluster controller is why I ask.
Corollary question, can you setup FCI without a replica? also when restoring an FCI databsae do you have to remove the database from AlwaysOn first, restore, then add back to AlwaysOn?
Finally is anyone using AG for applications with stateful connections? What has been your experience?
edit: MultiSubnetFailover is the connection string parameter I was thinking of