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How to migrate your existing availability group infrastructure?
Most part of availability groups implemented in my area consists of two replicas meaning a WSFC with 2 cluster nodes at the low-level of the global architecture as shown above: So the question is how to achieve the migration of the above infrastructure from 2012 version to 2016 version (both Windows and SQL Server) with low downtime?
What happens if I fail to upgrade the availability group?
Downtime after the initial failover will depend on the number of databases in the Availability Group. If you plan on failing back to the original primary, this step will not be repeated when you fail back. Note. This article limits the discussion to the upgrade of SQL Server itself.
How to upgrade the second availability group in SQL Server?
General steps to upgrade a distributed availability group Backup all databases, including system databases, and those participating in the availability group. Upgrade and restart all secondary replicas of the second availability group (the downstream). Upgrade and restart all secondary replicas of the first availability group (the upstream).
When to upgrade the availability group replicas ( AG )?
To prevent the AG from unintended failovers during the upgrade process, remove availability failover from all synchronous-commit replicas before you begin. Do not upgrade the primary replica instance before failing over the AG to an upgraded instance with a secondary replica first.
How to add availability group to SQL Server?
The first 2 nodes run on Windows Server 2012 whereas the last 2 nodes run on Windows Server 2016. An availability group runs on the top of the first 2 nodes and two additional replicas are ready to be enrolled to the existing infrastructure. So now let’s move on the SQL Server side and let’s add the 2 additional replicas.
Are there plans to migrate SQL Server 2012?
Have you already a plan to migrate your old SQL Server 2012 availability group infrastructure to windows 2016 and SQL Server 2016?
How many nodes are in an availability group?
The transitioned infrastructure includes now 4 nodes. The first 2 nodes run on Windows Server 2012 whereas the last 2 nodes run on Windows Server 2016. An availability group runs on the top of the first 2 nodes and two additional replicas are ready to be enrolled to the existing infrastructure.