We have two SQL servers combined into Availability Group in primary data center (dc1):
dc1 server 1: SQL Server 2012 SP3 on Windows 2016 dc1 server 2: SQL Server 2012 SP3 on Windows 2012 R2
We are going to open new data center (dc2) which is going eventually to be new primary data center In dc2 there is going to be third SQL server
dc2 server 3: SQL Server 2016 (or 2012) on Windows 2016
We would like to have SQL Server 2016 on server 3, but here are my questions:
1) --> What are potential problems if we add SQL Server 2016 as a third node to existing Availability Group that has two SQL Servers 2012?
2) --> Will AG be working properly or ? If you have any practical experience of doing so, please share
3) --> Do we really need to deploy server 3 as SQL Server 2012 (instead of 2016) in order for AG to be working ?
4) --> What are best options (aside of AG) to keep SQL servers 1, 2, and 3 in sync if we chose to deploy server 3 as SQL Server 2016 ? is that transactional replication
Thanks in advance!