Here I have a 2-node SQL Server 2016 AlwaysOn Availability Group cluster, with 1 primary and 1 secondary.
The question is – what is the optimal way to install Microsoft Updates on the servers in the cluster? I have struggled to find good, clear recommendations on this.
Here is my current thinking:
- Install updates using Microsoft Update on the secondary
- Restart the secondary to finish the updates
- Perform a manual failover from the Primary to the Secondary
- Install updates using Microsoft Update on the new-secondary (former primary)
- Restart the new-secondary (former primary)
- Perform a manual failover from the new-Primary to the Secondary, making the original primary the primary again
My understanding is that this will:
- Cause absolutely no application downtime
- Cause no syncing errors
- Cause no data corruption
- The cluster will not generate errors when half the nodes are updated and the other half are not
Is this correct? Is there a better way to do this?
Thanks in advance – any help is greatly appreciated.