Recently, our Windows 2012 SQL environment, running on Windows 2012 needed to move to Windows 2012 R2, and carry the SQL Cluster along with it. Unfortunately, there was no upgrade path for this kind of move, so we decided to backup the databases, blow everything away, and start from scratch.
Additionally, we were using a SANless setup. Without a SAN, we were using SIOS SteelEye DataKeeper to provide SAN functionality. It was mirroring a volume on our Primary SQL server to the Secondary SQL server. And on top of this we were running SQL Server 2012 as an AlwaysOn availability group.
First, we backup the databases. Next, we made a careful note of the SQL server network name (the name of the AlwaysOn cluster), so we could use the name again, and the SQL connection strings wouldn’t break.
At this point, we’re ready to re-install the OS. After this is done, we go into Active Directory Users & Computers, and delete the old Failover Cluster and SQL Cluster computer objects. If you don’t, the new clusters will try to use the old objects, but the GUID’s wont match, and you’ll end up with cluster setup problems. Also, be sure to delete the old DNS records for these as well.
For the next step, follow these two walkthroughs. They’re excellent articles to take you through the rest of the process. One thing to note before beginning. SIOS DataKeeper introduced support for Windows Server 2012 R2 in version 8.0. Version 7.x and below only support up Windows Server 2003-2012, not 2012 R2. Make sure you’ve got the right version.
When you’re all done, hand it over to the DBA’s and the WEB guys and go drink a well-earned beer (or two).