We recently upgraded our SQL Server and Windows Server on our production server from Windows Server 2008R2 and SQL server 2008R2 to Windows Server 2016 and SQL 17. I will qualify this by saying that I do not recommend waiting this long to perform these upgrades. However, this was a very stable environment for us for years, given that I am the only person in our agency managing our GIS environment. I just wanted to let the community know how this upgrade went. The SQL upgrade was performed first, and it went seamlessly. The test and cut over was very smooth. I had to contact our personnel to change the SQL instance to the new database, and then there were some minor items working with our enterprise SQL person.
Next came the OS upgrade, this was a little more involved, because we chose to upgrade our ArcGIS Enterprise software to 10.7.1 as well. The challenge came from having to set up a new server so that we could keep our old prod server running at the same time and to add to the challenge, we have about 60 to 70 web services that we were serving as well. So, I worked with Esri support to try a few things hoping to recreate the map services on the new server without creating them manually.
Esri has a backup tool for the server, that would work great if I was shutting down the old server, updating the OS on a new server, and then restoring the server to the new server keeping the original server's name. So, this was not an option. I also tried the Enterprise builder option, because this was a new server; however, I ran into some configuration issues and ended up uninstalling and reinstalling some of the components.
So, what worked the best for me was following the ArcGIS 10.7 deployment instructions
I was able to use the saved configuration files from earlier deployments, and this worked the best for my setup.