Microsoft SQL 2008 R2 had been officially supported for VMware vSphere 4.1 update 1. Previously it doesn’t supported if you are not on update 1. I just did an upgrade yesterday and here is some finding to share. 1st, I tried to perform an upgrade as usual, and of course I retain all the database information to prevent reconfiguration and performance data lost for the previous environment. Unfortunately, the update manager portion had given error which it not allowed us to continue the installation. It left me no choice that a re installation will be required. If you hit to the same situation, do not panic as your previous configuration will still retain, and no down time require even you are on dVswitch. Ensure no host name changes in this case will be safe enough for you to proceed further.

During the re-installation, you I will suggest you follow the sequence to un-install all the vCenter application 1 by 1. Update Manager required to be un-install before you uninstall the vCenter server. You can backup and re-attach the SQL DB as the MDF and LDF files is in place. If your vCenter is on virtual environment, strongly recommend a snapshot taken before any changes been made. Once you re-attach the DB, you will require to perform the DSN connections to be created from ODBC.

Here is the tricky part you need to take note. It take me 2 hours to figure out due to some confuse and mistake. vCenter Server will able to run on 64 bits DSN as standard, you will not face any issue on that. When come to update manager, DO NOT try to access the ODBCAD32.exe from start run directly on windows. It will point you to the 64 bits ODBC configuration tab. You will require to browse to the path directly as :

%systemdrive%\Windows\SysWoW64\Odbcad32.exe

Honestly speaking, I had no idea why windows had this issue which you required to manually execute the file follow the full path rather than the auto search, this I leave it to Microsoft to explain :) . Once you launch the right odbcad32.exe, you will able to access the 32 bit ODBC to create the DSN as usual. How you compare whether is correct, the DSN on the vCenter server that you created on 64 bits will not shown on the 32 bits. Then of course you can continue whatever necessary installation to complete the upgrade or installation as usual. Good Luck!!!!!!