W have a SQL 2008 R2 cluster set up as an active/active. We had the default instance running on the A side and three other instances running on the B. Before I got here, they needed to patch to SP2 CU5 to fix an issue with one of the applications using the server. The A side was successfully patched, but there was a problem on the B side.The admin had to restore the operating system from backup. This caused some of the original installation files to disappear. Consequently the update could not find necessary files and failed. The two sides are now at different version levels. The cluster was switched to an active/passive with the B side being the passive.
I am not sure how to fix this issue. I am thinking we may need to do a complete reinstall of SQL on B, but that is convoluted with 4 different instances and analysis services and reporting services all installed.
I have not worked with a sql cluster since 2007. (SQL2005).
“I know that you believe you understand what you think I said, but I'm not sure you realize that what you heard is not what I meant.”...Robert McCloskey