Hi Alejandro,

Thanks for this nice post. However I have few questions. I have active/active two nodes cluster setup with one node SQL Server 2008 R2 and the other node SQL Server 2005. Now the application manager wants me to upgrade the SQL 2005 node to SQL 2008 R2. The databases on 2005 instance are having Compatibility Level of SQL 2000 and he does not want to change that so databases will still be SQL 2000 even after SQL upgrade to 2008 R2.

In this scenario I think in-place upgrade is the only option I have. But what is the biggest risk? AND Does in-place upgrade process will also upgrade my databases to 2008 R2 level?

Note: OS is Windows 2008 R2 on both nodes.