Apply SP3 on SQL Server 2012 AlwaysOn AAGs

Question

If Always-On is configured, while applying Service Pack, should I:

• Directly move SQL Server Instance (Secondary Replica) to make it passive and apply Service Pack
• Or First move Availability Group and then move SQL Server Instance (Secondary Replica) and finally apply patch and restart the Server.

Can you please let me know?

Answer 1

Before an upgrade, you should:

• Perform a full backup of every database
• Try a manual failover. Make sure the AG fails over a Synchronous replicas and that the synchronization state of the replicas is SYNCHRONIZED
• Disable automatic backups on Secondary while they are being upgraded
• Disable automatic backups on Primary before the upgrade of Primary
• Do not upgrade Primary before any or all of the Secondary.

Then here is the Rolling Upgrade Process:

1. Remove automatic failover on all synchronous-commit replicas
2. Upgrade all asynchronous-commit secondary replica instances
3. Upgrade all remote synchronous-commit secondary replica instances
4. Upgrade all local synchronous-commit secondary replica instances
5. Manually fail over the AG to a (newly upgraded) local synchronous-commit secondary replica (see Perform a planned manual failover of an Always On availability group on Microsoft Docs)
6. Upgrade or update the local replica instance that formerly hosted the primary replica.
7. Configure automatic failover partners as desired.